Derniers messages sur Zeste de Savoirhttps://zestedesavoir.com/forums/2019-01-21T20:31:56+01:00Les derniers messages parus sur le forum de Zeste de Savoir.Pouvoir tampon d'un acide volatil (CO2), message #1978272019-01-21T20:31:56+01:00Akio/@Akiohttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197827<p>Oups oui, <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span>, <del>je vais corriger ça.</del> edit : corrigé <img src="/static/smileys/smile.png" alt=":)" class="smiley"></p>
<p>Pour ton message précédent, non, je pense que c’est simplement une façon maladroite d’expliquer le pouvoir tampon du CO2 dans le sang.</p>
<p>Tu décompose un peut trop ce qu’il se passe. Le système est ouvert (d’où la pression partielle constante), la solution est saturée en CO2, tout l’acide carbonique que tu produis se déshydrate et passe en phase gazeuse.<br>
Alors oui, si on voulait pinailler on pourrait résoudre l’équation du second degrés pour calculer précisément l’avancement puis les concentration du nouvel équilibre et on se rendrait compte qu’en prenant les même chiffres de départ ( 24 mmol et 1.2 mmol) et en arrondissant à <strong>6 chiffres significatifs</strong> l’avancement serait de 1.000000 mmol au lieu de … 1 mmol, ça change absolument rien (et oui j’ai fait le calcul avec 8 chiffres et le résultat, sans arrondir au même nombre de chiffres c’était 0.99999995652174)</p>
<p>Que le CO2 passe immédiatement ou non en phase gazeuse, ça ne change rien, ce qui compte c’est l’état d’équilibre et à l’équilibre il y a forcément toujours la même quantité de CO2 dissous puisque cette quantité dépends de la pression partielle qui est constante. </p>Pouvoir tampon d'un acide volatil (CO2), message #1978242019-01-21T18:21:31+01:00nainposteur/@nainposteurhttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197824<p>Oui je ne vois pas bien l’utilité du second calcul.
Tu veux dire l’acide avec lequel réagirait <strong>HCO3-</strong> plutôt non ? </p>
<p>Ben ce que je veux dire c’est que une fois que HCl à réagis avec HCO3-, il y a une partie de CO2 dissout qui va passer en phase gazeuse étant donné que la concentration de CO2 dissout a tendance a augmenter mais que la pression partiel de CO2 n’a pas (encore) augmenté. En passant en phase gazeuse, il y a alors une diminution de la concentration de CO2 dissout (donc de H2CO3 si tu préfères) en solution. Ce qui déplace l’état d’équilibre de la réaction (H+) + HCO3- = H2CO3 dans le sens de consommation des ions HCO3- . Or tu ne l’a pas pris en compte. Est-ce faux de dire cela ? </p>
<p>Ben peu importe d’ou il vient, le fait est qu’en passant en phase gazeuse, le CO2 dissout modifie l’équilibre. Mais du peu d’ions (H3O+) de la solution très probablement. Puisque même ci la réaction avec HCl est total, on a quand même la réaction H2CO3 + H2O = (H3O+) + HCO3- . </p>
<p>Et du coup tu peux répondre à la première question de mon message précédent s’il te plait ? </p>Pouvoir tampon d'un acide volatil (CO2), message #1978212019-01-21T17:38:09+01:00Akio/@Akiohttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197821<p>Et il viendrait d’où l’acide avec le quel réagirait <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> dans ce cas ? La solution est à nouveau à l’équilibre. </p>
<p>Si tu fait le calcul à l’envers : <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>p</mi><mi>K</mi><mi>a</mi><mo>=</mo><mo>−</mo><mi>l</mi><mi>o</mi><mi>g</mi><mo>(</mo><mfrac><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msup><mi>H</mi><mo>+</mo></msup><mo>]</mo></mrow><mrow><mo>[</mo><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub><mo>]</mo></mrow></mfrac><mo>)</mo><mo>=</mo><mo>−</mo><mi>l</mi><mi>o</mi><mi>g</mi><mo>(</mo><mfrac><mrow><mn>23</mn><mo>∗</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>7.38</mn></mrow></msup></mrow><mn>1.2</mn></mfrac><mo>)</mo><mo>=</mo><mn>6.1</mn></mrow><annotation encoding="application/x-tex">pKa = -log(\frac{[HCO_3^-][H^+]}{[H_2CO_3]}) = -log(\frac{23 * 10^{-7.38}}{1.2}) = 6.1</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8777699999999999em;vertical-align:-0.19444em;"></span><span class="mord mathdefault">p</span><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="mord mathdefault">a</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:1.623565em;vertical-align:-0.52em;"></span><span class="mord">−</span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.03588em;">g</span><span class="mopen">(</span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.103565em;"><span style="top:-2.655em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mopen mtight">[</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.08125em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span><span class="mclose mtight">]</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.5102em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mopen mtight">[</span><span class="mord mathdefault mtight" style="margin-right:0.08125em;">H</span><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8476642857142856em;"><span style="top:-2.214em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">3</span></span></span><span style="top:-2.931em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.286em;"><span></span></span></span></span></span></span><span class="mclose mtight">]</span><span class="mopen mtight">[</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.8476642857142858em;"><span style="top:-2.931em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mclose mtight">]</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.52em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mclose">)</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:1.36292em;vertical-align:-0.345em;"></span><span class="mord">−</span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.03588em;">g</span><span class="mopen">(</span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.01792em;"><span style="top:-2.6550000000000002em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">1</span><span class="mord mtight">.</span><span class="mord mtight">2</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">3</span><span class="mbin mtight">∗</span><span class="mord mtight">1</span><span class="mord mtight"><span class="mord mtight">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.8913142857142857em;"><span style="top:-2.931em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight"><span class="mord mtight">−</span><span class="mord mtight">7</span><span class="mord mtight">.</span><span class="mord mtight">3</span><span class="mord mtight">8</span></span></span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mclose">)</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">6</span><span class="mord">.</span><span class="mord">1</span></span></span></span></span> tu retrouve bien ton Ka ce qui énerverai un mathématicien puisque s’est un peut bête de faire cette vérification, le résultat est évident vu qu’on c’est servi de la même constante pour arriver au pH.</p>Pouvoir tampon d'un acide volatil (CO2), message #1978172019-01-21T16:35:27+01:00nainposteur/@nainposteurhttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197817<p>Ah, mais je croyais que quand on parlais de mesurer le pouvoir tampon de l’acide volatil, il s’agissait justement d’essayer de gommer le plus possible les effets du passage en phase gazeuse du CO2 formé suite à la réaction HCO3- avec HCl. Si je comprend bien, il s’agissait au contraire de se rapprocher des conditions physiologique en évacuant le CO2 passé en phase gazeuse ? </p>
<p>Merci beaucoup pour ton explication Akio, mais une question demeure. Dans ton calcul, tu fais comme si le passage du CO2 en phase gazeuse ne modifiait pas la concentration de HCO3-, alors qu’en réalité, cela va faire diminuer aussi la concentration de HCO3-, qu’est-ce qui justifie cela ? </p>Pouvoir tampon d'un acide volatil (CO2), message #1977532019-01-20T21:00:32+01:00Akio/@Akiohttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197753<figure><blockquote>
<p>Lorsqu’on va commencer a titrer la solutions avec du HCl, les ions HCO3- vont réagir avec HCl pour former du CO2 dissout.</p>
</blockquote><figcaption><a href="https://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197649">nainposteur</a></figcaption></figure>
<p>Ouais, mais avant ça y’à les <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow><annotation encoding="application/x-tex">CO_3^{2-}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.120547em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.854239em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">−</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> qui vont réagir aussi. On les as oublié au début mais dans cette histoire il y a deux couples mis en jeux : <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mi mathvariant="normal">/</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^- / CO_3^{2-}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.120547em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mord">/</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.854239em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">−</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> pKa = 10,32 et <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub><mi mathvariant="normal">/</mi><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">H_2CO_3/HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord">/</span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> pKa = 6,37 (6,1 dans le sang).</p>
<p>La troisième réaction qui nous intéresse c’est l’hydratation du <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow><annotation encoding="application/x-tex">CO_2</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span> en <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow><annotation encoding="application/x-tex">H_2CO_3</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span> K = 1.7 * 10<sup>-3</sup> et là je parle que du CO2 dissous, donc il y a encore la loi de Henry a appliquer a la pression partielle de CO2 gazeux avant (avec une constante de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub><mi mathvariant="normal">/</mi><mo>[</mo><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub><msub><mo>]</mo><mrow><mi>a</mi><mi>q</mi></mrow></msub><mo>≈</mo><mn>29</mn><mi>L</mi><mi mathvariant="normal">.</mi><mi>a</mi><mi>t</mi><mi>m</mi><mi mathvariant="normal">/</mi><mi>m</mi><mi>o</mi><mi>l</mi></mrow><annotation encoding="application/x-tex">P_{CO_2}/[CO_2]_{aq} \approx 29 L.atm/mol</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.036108em;vertical-align:-0.286108em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span><span class="mord">/</span><span class="mopen">[</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mclose"><span class="mclose">]</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.15139200000000003em;"><span style="top:-2.5500000000000003em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathdefault mtight">a</span><span class="mord mathdefault mtight" style="margin-right:0.03588em;">q</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.286108em;"><span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">≈</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">2</span><span class="mord">9</span><span class="mord mathdefault">L</span><span class="mord">.</span><span class="mord mathdefault">a</span><span class="mord mathdefault">t</span><span class="mord mathdefault">m</span><span class="mord">/</span><span class="mord mathdefault">m</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span></span></span></span></span>) . </p>
<p>Essaye d’écrire les réactions, tu y verras déjà plus clair.</p>
<p>Je vais t’en donner une puisque c’est celle qui nous intéresse : </p>
<p><span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>+</mo><msup><mi>H</mi><mo>+</mo></msup><mo>⇆</mo><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow><annotation encoding="application/x-tex">HCO_3^- + H^+ \leftrightarrows H_2CO_3</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2222222222222222em;"></span><span class="mbin">+</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span></span><span class="base"><span class="strut" style="height:0.952131em;vertical-align:-0.1808em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel amsrm">⇆</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span></p>
<p>Blackline a déjà écrit les constantes plus haut, je ne vais pas les remettre.</p>
<p>Là on est à l’équilibre, pour que ça soit plus simple a comprendre on va prendre des chiffres : </p>
<ul>
<li>24 mmol/L de bicarbonate <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> </li>
<li>1.2 mmol/L de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow><annotation encoding="application/x-tex">H_2CO_3</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span><br>
Ce qui nous donnes un pH de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>6.1</mn><mo>+</mo><mi>l</mi><mi>o</mi><mi>g</mi><mfrac><mn>24</mn><mn>1.2</mn></mfrac><mo>=</mo><mn>7.40</mn></mrow><annotation encoding="application/x-tex">6.1 + log\frac{24}{1.2} = 7.40</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.72777em;vertical-align:-0.08333em;"></span><span class="mord">6</span><span class="mord">.</span><span class="mord">1</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span><span class="mbin">+</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span></span><span class="base"><span class="strut" style="height:1.190108em;vertical-align:-0.345em;"></span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.03588em;">g</span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.845108em;"><span style="top:-2.6550000000000002em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">1</span><span class="mord mtight">.</span><span class="mord mtight">2</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">4</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">7</span><span class="mord">.</span><span class="mord">4</span><span class="mord">0</span></span></span></span></span>, tant mieux, c’est une valeur dans la norme </li>
</ul>
<p>Maintenant imaginons que le système est fermé et qu’on ajoute 1 mmol de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msup><mi>H</mi><mo>+</mo></msup></mrow><annotation encoding="application/x-tex">H^+</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.771331em;vertical-align:0em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span></span></span></span></span> (a 1L de sang), comme tu l’as dit en premier, dans ce cas, on forme du CO2 mais qui a cause de sa pression partielle reste en solution, ça reviens donc a "ajouter" 1 mmol de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow><annotation encoding="application/x-tex">H_2CO_3</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span> et "retirer" 1 mmol de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> si on en croit l’équation que j’ai donné (à peut près puisque comme tu l’a dit va contribuer a augmenter la pression partielle).</p>
<p>Mon calcul de pH deviens donc : <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>p</mi><mi>H</mi><mo>=</mo><mn>6.1</mn><mo>+</mo><mi>l</mi><mi>o</mi><mi>g</mi><mfrac><mn>23</mn><mn>2.2</mn></mfrac><mo>=</mo><mn>7.12</mn></mrow><annotation encoding="application/x-tex">pH = 6.1 + log\frac{23}{2.2} = 7.12</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8777699999999999em;vertical-align:-0.19444em;"></span><span class="mord mathdefault">p</span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.72777em;vertical-align:-0.08333em;"></span><span class="mord">6</span><span class="mord">.</span><span class="mord">1</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span><span class="mbin">+</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span></span><span class="base"><span class="strut" style="height:1.190108em;vertical-align:-0.345em;"></span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.03588em;">g</span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.845108em;"><span style="top:-2.6550000000000002em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">.</span><span class="mord mtight">2</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">3</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">7</span><span class="mord">.</span><span class="mord">1</span><span class="mord">2</span></span></span></span></span> Le médecin commence à s’inquiéter là </p>
<p>Maintenant dans un système ouvert, la pression partielle de CO2 reste constante (puisque le CO2 excédentaire est éliminé (par la respiration dans le cas du corps)) donc la concentration en acide carbonique aussi, le pH est alors de : <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>6.1</mn><mo>+</mo><mi>l</mi><mi>o</mi><mi>g</mi><mfrac><mn>23</mn><mn>1.2</mn></mfrac><mo>=</mo><mn>7.38</mn></mrow><annotation encoding="application/x-tex">6.1 + log\frac{23}{1.2} = 7.38</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.72777em;vertical-align:-0.08333em;"></span><span class="mord">6</span><span class="mord">.</span><span class="mord">1</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span><span class="mbin">+</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span></span><span class="base"><span class="strut" style="height:1.190108em;vertical-align:-0.345em;"></span><span class="mord mathdefault" style="margin-right:0.01968em;">l</span><span class="mord mathdefault">o</span><span class="mord mathdefault" style="margin-right:0.03588em;">g</span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.845108em;"><span style="top:-2.6550000000000002em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">1</span><span class="mord mtight">.</span><span class="mord mtight">2</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mtight">3</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">7</span><span class="mord">.</span><span class="mord">3</span><span class="mord">8</span></span></span></span></span>, on reste dans des valeurs normales.</p>
<p>En gros cette histoire de pression partielle constante, c’est pour expliquer l’effet tampon du CO2 dans le sang. Pour le dosage pH-métrique, on s’en fout un peu, pression partielle constante ou pas on a le même volume équivalent</p>
<p>Et je ne comprends pas pourquoi on vous expliques ça de cette façon puisque PERSONNE ne dose le Bicarbonate dans le sang de cette manière, on utilise une méthode enzymatique sur des automates type COBAS … certes ça explique en partie comment le corps maintient son pH a + ou - 0.02 unité prés par élimination de CO2 dans les poumons, mais niveau analyses y’a mieux x)</p>Pouvoir tampon d'un acide volatil (CO2), message #1976492019-01-19T13:13:17+01:00nainposteur/@nainposteurhttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197649<p>Malheureusement, je n’arrive toujours pas à comprendre cette histoire de pression constante. </p>
<p>Pour moi on a : Au début, une solution avec une certaine quantité en (HCO3-), de CO2 dissout et pression partiel Pi de CO2 gazeux, tout ceci à l’équilibre. Lorsqu’on va commencer a titrer la solutions avec du HCl, les ions HCO3- vont réagir avec HCl pour former du CO2 dissout. Or, on est alors plus à l’équilibre avec la pression partiel de CO2, le CO2 dissout va alors avoir tendance à passer en phase gazeuse pour atteindre un nouvel état d’équilibre. La pression partiel de CO2 augmente alors, et sa concentration en solution diminue donc. Ce qui d’après le principe de Chatelier déplace alors l’équilibre de la réaction acide/base vers la consommations des ions (HCO3-) pour redonner du CO2 dissout. Or même si l’on maintient la pression constante à Pi au cours du titrage en faisant sortir le CO2 gazeux se formant, le CO2 dissout a quand même tendance à diminuer, ce qui modifie la concentration en ions (H3O+) . J’aurais donc tendance à penser qu’au lieu de faire sortir le CO2 qui passe en phase gazeuse, il faille augmenter au fur et a mesure du titrage la pression de CO2 afin que le CO2 dissout se formant au cours du titrage ne passe pas en phase gazeuse. </p>Pouvoir tampon d'un acide volatil (CO2), message #1976452019-01-19T11:53:22+01:00Akio/@Akiohttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197645<figure><blockquote>
<p>Si la pression de CO2 reste constante, la concentration de CO2 dissout l’ait alors elle aussi, ce qui signifie donc qu’il n’y a pas eu de HCO3- qui ont réagi lors du titrage, sinon il y aurait eu du CO2 formé, et la pression ne serait pas constante.</p>
</blockquote><figcaption><a href="https://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197620">nainposteur</a></figcaption></figure>
<p>Justement non, il n’y a rien qui empêche <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow><annotation encoding="application/x-tex">HCO_3^-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0777700000000001em;vertical-align:-0.266308em;"></span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span></span></span></span></span> de réagir si tu maintiens la pression constante.Maintenir une pression constante ça veux aussi dire que si elle augmente tu peux laisser sortir un peut de gaz pour rester à la même valeur. </p>Pouvoir tampon d'un acide volatil (CO2), message #1976202019-01-19T00:06:37+01:00nainposteur/@nainposteurhttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197620<p>Je ne comprend pas trop je crois. Lorsqu’on va titrer avec HCl . On va avoir des ions (HCO3-) qui vont former du CO2 dissous, qui va alors passer en partie en phase gazeuse pour respecter l’équation [H2CO3]=S*P(CO2) . Si la pression de CO2 reste constante, la concentration de CO2 dissout l’ait alors elle aussi, ce qui signifie donc qu’il n’y a pas eu de HCO3- qui ont réagi lors du titrage, sinon il y aurait eu du CO2 formé, et la pression ne serait pas constante.
J’imagine bien que mon raisonnement est mauvais, mais j’arrive pas du tout à comprendre :/ </p>Pouvoir tampon d'un acide volatil (CO2), message #1975472019-01-18T04:51:20+01:00Blackline/@Blacklinehttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197547<p>Coucou nainposteur,</p>
<div class="custom-block custom-block-question"><div class="custom-block-body"><p>Pourquoi maintenir la concentration de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mrow><mi mathvariant="normal">C</mi><mi mathvariant="normal">O</mi></mrow><mn>2</mn></msub></mrow><annotation encoding="application/x-tex">\mathrm{CO}_2</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord"><span class="mord mathrm">C</span><span class="mord mathrm">O</span></span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span> constante dans la solution ?</p></div></div>
<p>J’imagine que c’est en rapport direct avec la loi de Lechatelier<sup id="fnref-1-CzBpDn1V1m"><a href="#fn-1-CzBpDn1V1m" class="footnote-ref">1</a></sup> et plus directement avec la loi d’action de masse :</p>
<div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>K</mi><mo>=</mo><munder><mo>∏</mo><mi>i</mi></munder><mo>(</mo><msub><mi>a</mi><mi>i</mi></msub><msup><mo>)</mo><msub><mi>ν</mi><mi>i</mi></msub></msup></mrow><annotation encoding="application/x-tex">K = \prod_i (a_i)^{\nu_i}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.68333em;vertical-align:0em;"></span><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:2.327674em;vertical-align:-1.277669em;"></span><span class="mop op-limits"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.0500050000000003em;"><span style="top:-1.872331em;margin-left:0em;"><span class="pstrut" style="height:3.05em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">i</span></span></span><span style="top:-3.050005em;"><span class="pstrut" style="height:3.05em;"></span><span><span class="mop op-symbol large-op">∏</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:1.277669em;"><span></span></span></span></span></span><span class="mopen">(</span><span class="mord"><span class="mord mathdefault">a</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31166399999999994em;"><span style="top:-2.5500000000000003em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">i</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mclose"><span class="mclose">)</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7143919999999999em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.06366em;">ν</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3280857142857143em;"><span style="top:-2.357em;margin-left:-0.06366em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mathdefault mtight">i</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div>
<p>Qui ici s’écrit comme ceci<sup id="fnref-2-CzBpDn1V1m"><a href="#fn-2-CzBpDn1V1m" class="footnote-ref">2</a></sup>, pour la réaction que je me permet de réécrire à partir du constat que <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>C</mi><msub><mi>O</mi><mrow><mn>2</mn><mo>(</mo><mi>d</mi><mi>i</mi><mi>s</mi><mi>s</mi><mi>o</mi><mi>u</mi><mi>t</mi><mo>)</mo></mrow></msub><mo>=</mo><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow><annotation encoding="application/x-tex">CO_{2(dissout)} = H_2CO_3</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.03853em;vertical-align:-0.3551999999999999em;"></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.34480000000000005em;"><span style="top:-2.5198em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mopen mtight">(</span><span class="mord mathdefault mtight">d</span><span class="mord mathdefault mtight">i</span><span class="mord mathdefault mtight">s</span><span class="mord mathdefault mtight">s</span><span class="mord mathdefault mtight">o</span><span class="mord mathdefault mtight">u</span><span class="mord mathdefault mtight">t</span><span class="mclose mtight">)</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.3551999999999999em;"><span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span></p>
<div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>K</mi><mi>a</mi></msub><mo>=</mo><mfrac><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow><msub><mi>a</mi><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></mrow></msub></mfrac><mo>=</mo><mfrac><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow></mfrac></mrow><annotation encoding="application/x-tex">K_a = \dfrac{[HCO_3^-][H_3O^+]}{a_{H_2CO_3}} = \dfrac{[HCO_3^-][H_3O^+]}{SP_{CO_2}}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.07153em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">a</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:2.4245620000000003em;vertical-align:-0.9361em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.4884620000000002em;"><span style="top:-2.314em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord"><span class="mord mathdefault">a</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.08125em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.677em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mopen">[</span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mclose">]</span><span class="mopen">[</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mclose">]</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.9361em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:2.4245620000000003em;vertical-align:-0.9361em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.4884620000000002em;"><span style="top:-2.314em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.05764em;">S</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.677em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mopen">[</span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mclose">]</span><span class="mopen">[</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mclose">]</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.9361em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span></span></span></span></span></div>
<p><span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>K</mi><mi>a</mi></msub></mrow><annotation encoding="application/x-tex">K_a</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.07153em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">a</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span> étant la constante d’acidité intrinséque, elle ne varie pas, elle stagnera à <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>K</mi><mi>a</mi></msub><mo>=</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>6.37</mn></mrow></msup></mrow><annotation encoding="application/x-tex">K_a=10^{-6.37}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.07153em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">a</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.8141079999999999em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord"><span class="mord">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.8141079999999999em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">−</span><span class="mord mtight">6</span><span class="mord mtight">.</span><span class="mord mtight">3</span><span class="mord mtight">7</span></span></span></span></span></span></span></span></span></span></span></span></span>. (Par rapport à son <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>p</mi><msub><mi>K</mi><mi>a</mi></msub></mrow><annotation encoding="application/x-tex">pK_a</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8777699999999999em;vertical-align:-0.19444em;"></span><span class="mord mathdefault">p</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.07153em;">K</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.07153em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">a</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span>…). Donc nous avons l’immuable :</p>
<div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mfrac><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow></mfrac><mo>=</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>6.37</mn></mrow></msup></mrow><annotation encoding="application/x-tex">\dfrac{[HCO_3^-][H_3O^+]}{SP_{CO_2}} = 10^{-6.37}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:2.4245620000000003em;vertical-align:-0.9361em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.4884620000000002em;"><span style="top:-2.314em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.05764em;">S</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.677em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mopen">[</span><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;">C</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mclose">]</span><span class="mopen">[</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mclose">]</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.9361em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:0.864108em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord"><span class="mord">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.864108em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">−</span><span class="mord mtight">6</span><span class="mord mtight">.</span><span class="mord mtight">3</span><span class="mord mtight">7</span></span></span></span></span></span></span></span></span></span></span></span></span></div>
<p>Tu te doute bien que si <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow><annotation encoding="application/x-tex">P_{CO_2}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.93343em;vertical-align:-0.2501em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.07153em;">C</span><span class="mord mtight"><span class="mord mathdefault mtight" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight"><span class="mord mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span></span></span></span></span> varie, on change obligatoirement ce qui a au dessus de la barre de fraction. Ce qui va diminuer la quantité de <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow><annotation encoding="application/x-tex">[H_3O^+]</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.021331em;vertical-align:-0.25em;"></span><span class="mopen">[</span><span class="mord"><span class="mord mathdefault" style="margin-right:0.08125em;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.02778em;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mbin mtight">+</span></span></span></span></span></span></span></span><span class="mclose">]</span></span></span></span></span> que tu tentais de mesurer !</p>
<hr>
<p><strong>EDIT :</strong></p>
<div class="custom-block custom-block-spoiler"><div class="custom-block-body"><div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mfrac><mstyle mathcolor="red"><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow></mstyle><mstyle mathcolor="blue"><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow></mstyle></mfrac><mo>=</mo><mfrac><mstyle mathcolor="red"><mrow><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>6.37</mn></mrow></msup></mrow></mstyle><mstyle mathcolor="blue"><mn>1</mn></mstyle></mfrac></mrow><annotation encoding="application/x-tex">\dfrac{\color{red}{[HCO_3^-][H_3O^+]}}{\color{blue}{SP_{CO_2}}} = \dfrac{\color{red}{10^{-6.37}}}{\color{blue}{1}}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:2.4245620000000003em;vertical-align:-0.9361em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.4884620000000002em;"><span style="top:-2.314em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord" style="color:blue;"><span class="mord mathdefault" style="margin-right:0.05764em;color:blue;">S</span><span class="mord" style="color:blue;"><span class="mord mathdefault" style="margin-right:0.13889em;color:blue;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:blue;"><span class="mord mtight" style="color:blue;"><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:blue;">C</span><span class="mord mtight" style="color:blue;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:blue;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:blue;"><span class="mord mtight" style="color:blue;">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.677em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord" style="color:red;"><span class="mopen" style="color:red;">[</span><span class="mord mathdefault" style="margin-right:0.08125em;color:red;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;color:red;">C</span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.811462em;"><span style="top:-2.433692em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span><span style="top:-3.1031310000000003em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.266308em;"><span></span></span></span></span></span></span><span class="mclose" style="color:red;">]</span><span class="mopen" style="color:red;">[</span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.08125em;color:red;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.771331em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">+</span></span></span></span></span></span></span></span><span class="mclose" style="color:red;">]</span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.9361em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:2.177108em;vertical-align:-0.686em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:1.491108em;"><span style="top:-2.314em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord" style="color:blue;"><span class="mord" style="color:blue;">1</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.677em;"><span class="pstrut" style="height:3em;"></span><span class="mord"><span class="mord" style="color:red;"><span class="mord" style="color:red;">1</span><span class="mord" style="color:red;"><span class="mord" style="color:red;">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.8141079999999999em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;"><span class="mord mtight" style="color:red;">−</span><span class="mord mtight" style="color:red;">6</span><span class="mord mtight" style="color:red;">.</span><span class="mord mtight" style="color:red;">3</span><span class="mord mtight" style="color:red;">7</span></span></span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.686em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span></span></span></span></span></div><div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mstyle mathcolor="red"><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo><mo>=</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>6.37</mn></mrow></msup></mrow><mrow><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mstyle mathcolor="black"><mrow><mi mathvariant="normal">l</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">q</mi><mi mathvariant="normal">u</mi><mi mathvariant="normal">e</mi></mrow><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext></mstyle></mrow><mstyle mathcolor="blue"><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub><mo>=</mo><mn>1</mn></mrow></mstyle></mstyle></mrow><annotation encoding="application/x-tex">\color{red}{[HCO_3^-][H_3O^+] = 10^{-6.37} } \mathrm{\;\;\;\;\;\;\;\color{black}{lorsque}\;\;\;\;\;\;\;} \color{blue}{SP_{CO_2} = 1}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.120547em;vertical-align:-0.256439em;"></span><span class="mord" style="color:red;"><span class="mopen" style="color:red;">[</span><span class="mord mathdefault" style="margin-right:0.08125em;color:red;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;color:red;">C</span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8213309999999999em;"><span style="top:-2.4435610000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.256439em;"><span></span></span></span></span></span></span><span class="mclose" style="color:red;">]</span><span class="mopen" style="color:red;">[</span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.08125em;color:red;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord" style="color:red;"><span class="mord mathdefault" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.821331em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">+</span></span></span></span></span></span></span></span><span class="mclose" style="color:red;">]</span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mrel" style="color:red;">=</span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:red;">1</span><span class="mord" style="color:red;"><span class="mord" style="color:red;">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.864108em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:red;"><span class="mord mtight" style="color:red;"><span class="mord mtight" style="color:red;">−</span><span class="mord mtight" style="color:red;">6</span><span class="mord mtight" style="color:red;">.</span><span class="mord mtight" style="color:red;">3</span><span class="mord mtight" style="color:red;">7</span></span></span></span></span></span></span></span></span></span><span class="mord" style="color:red;"><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:red;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:black;"><span class="mord mathrm" style="color:black;">l</span><span class="mord mathrm" style="color:black;">o</span><span class="mord mathrm" style="color:black;">r</span><span class="mord mathrm" style="color:black;">s</span><span class="mord mathrm" style="color:black;">q</span><span class="mord mathrm" style="color:black;">u</span><span class="mord mathrm" style="color:black;">e</span></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span></span><span class="mord" style="color:blue;"><span class="mord mathdefault" style="margin-right:0.05764em;color:blue;">S</span><span class="mord" style="color:blue;"><span class="mord mathdefault" style="margin-right:0.13889em;color:blue;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:blue;"><span class="mord mtight" style="color:blue;"><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:blue;">C</span><span class="mord mtight" style="color:blue;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:blue;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:blue;"><span class="mord mtight" style="color:blue;">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span><span class="mspace" style="color:blue;margin-right:0.2777777777777778em;"></span><span class="mrel" style="color:blue;">=</span><span class="mspace" style="color:blue;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:blue;">1</span></span></span></span></span></span></div><p>Si maintenant <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mstyle mathcolor="olive"><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub><mo>=</mo><mn>0.5</mn></mrow></mstyle></mrow><annotation encoding="application/x-tex">\color{olive}{SP_{CO_2} = 0.5}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.93343em;vertical-align:-0.2501em;"></span><span class="mord" style="color:olive;"><span class="mord mathdefault" style="margin-right:0.05764em;color:olive;">S</span><span class="mord" style="color:olive;"><span class="mord mathdefault" style="margin-right:0.13889em;color:olive;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:olive;"><span class="mord mtight" style="color:olive;"><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:olive;">C</span><span class="mord mtight" style="color:olive;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:olive;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:olive;"><span class="mord mtight" style="color:olive;">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span><span class="mspace" style="color:olive;margin-right:0.2777777777777778em;"></span><span class="mrel" style="color:olive;">=</span><span class="mspace" style="color:olive;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:olive;">0</span><span class="mord" style="color:olive;">.</span><span class="mord" style="color:olive;">5</span></span></span></span></span></span> car tu as perdue du <span class="inlineMath"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi mathvariant="normal">C</mi><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></mrow><annotation encoding="application/x-tex">\mathrm{CO_2}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathrm">C</span><span class="mord"><span class="mord mathrm">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathrm mtight">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span></span></span>, alors :</p><div class="math"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mstyle mathcolor="orange"><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo><mo>=</mo><mn>2.133</mn><mo>×</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></mrow><mrow><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mstyle mathcolor="black"><mrow><mi mathvariant="normal">l</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">q</mi><mi mathvariant="normal">u</mi><mi mathvariant="normal">e</mi></mrow><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext><mtext> </mtext></mstyle></mrow><mstyle mathcolor="olive"><mrow><mi>S</mi><msub><mi>P</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub><mo>=</mo><mn>0.5</mn></mrow></mstyle></mstyle></mrow><annotation encoding="application/x-tex">\color{orange}{[HCO_3^-][H_3O^+] = 2.133\times 10^{-7}} \mathrm{\;\;\;\;\;\;\;\color{black}{lorsque}\;\;\;\;\;\;\;} \color{olive}{SP_{CO_2} = 0.5}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.120547em;vertical-align:-0.256439em;"></span><span class="mord" style="color:orange;"><span class="mopen" style="color:orange;">[</span><span class="mord mathdefault" style="margin-right:0.08125em;color:orange;">H</span><span class="mord mathdefault" style="margin-right:0.07153em;color:orange;">C</span><span class="mord" style="color:orange;"><span class="mord mathdefault" style="margin-right:0.02778em;color:orange;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8213309999999999em;"><span style="top:-2.4435610000000003em;margin-left:-0.02778em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:orange;"><span class="mord mtight" style="color:orange;">3</span></span></span><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:orange;"><span class="mbin mtight" style="color:orange;">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.256439em;"><span></span></span></span></span></span></span><span class="mclose" style="color:orange;">]</span><span class="mopen" style="color:orange;">[</span><span class="mord" style="color:orange;"><span class="mord mathdefault" style="margin-right:0.08125em;color:orange;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.30110799999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.08125em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:orange;"><span class="mord mtight" style="color:orange;">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord" style="color:orange;"><span class="mord mathdefault" style="margin-right:0.02778em;color:orange;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.821331em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:orange;"><span class="mbin mtight" style="color:orange;">+</span></span></span></span></span></span></span></span><span class="mclose" style="color:orange;">]</span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mrel" style="color:orange;">=</span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:orange;">2</span><span class="mord" style="color:orange;">.</span><span class="mord" style="color:orange;">1</span><span class="mord" style="color:orange;">3</span><span class="mord" style="color:orange;">3</span><span class="mspace" style="color:orange;margin-right:0.2222222222222222em;"></span><span class="mbin" style="color:orange;">×</span><span class="mspace" style="color:orange;margin-right:0.2222222222222222em;"></span><span class="mord" style="color:orange;">1</span><span class="mord" style="color:orange;"><span class="mord" style="color:orange;">0</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.864108em;"><span style="top:-3.113em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:orange;"><span class="mord mtight" style="color:orange;"><span class="mord mtight" style="color:orange;">−</span><span class="mord mtight" style="color:orange;">7</span></span></span></span></span></span></span></span></span></span><span class="mord" style="color:orange;"><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:orange;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:black;"><span class="mord mathrm" style="color:black;">l</span><span class="mord mathrm" style="color:black;">o</span><span class="mord mathrm" style="color:black;">r</span><span class="mord mathrm" style="color:black;">s</span><span class="mord mathrm" style="color:black;">q</span><span class="mord mathrm" style="color:black;">u</span><span class="mord mathrm" style="color:black;">e</span></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span><span class="mspace" style="color:black;margin-right:0.2777777777777778em;"></span></span><span class="mord" style="color:olive;"><span class="mord mathdefault" style="margin-right:0.05764em;color:olive;">S</span><span class="mord" style="color:olive;"><span class="mord mathdefault" style="margin-right:0.13889em;color:olive;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.32833099999999993em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style="color:olive;"><span class="mord mtight" style="color:olive;"><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:olive;">C</span><span class="mord mtight" style="color:olive;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:olive;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:olive;"><span class="mord mtight" style="color:olive;">2</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.2501em;"><span></span></span></span></span></span></span><span class="mspace" style="color:olive;margin-right:0.2777777777777778em;"></span><span class="mrel" style="color:olive;">=</span><span class="mspace" style="color:olive;margin-right:0.2777777777777778em;"></span><span class="mord" style="color:olive;">0</span><span class="mord" style="color:olive;">.</span><span class="mord" style="color:olive;">5</span></span></span></span></span></span></div><p><span class="inlineMath inlineMathDouble"><span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><munder><munder><mrow><mn>2.133</mn><mo>×</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></mrow><mo stretchy="true">⎵</mo></munder><mstyle mathcolor="orange"><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow></mstyle></munder><mo><</mo><munder><munder><mrow><mn>4.266</mn><mo>×</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mo>=</mo><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>6.37</mn></mrow></msup></mrow><mo stretchy="true">⎵</mo></munder><mstyle mathcolor="red"><mrow><mo>[</mo><mi>H</mi><mi>C</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup><mo>]</mo><mo>[</mo><msub><mi>H</mi><mn>3</mn></msub><msup><mi>O</mi><mo>+</mo></msup><mo>]</mo></mrow></mstyle></munder></mrow><annotation encoding="application/x-tex">\underbrace{2.133\times 10^{-7}}_{\color{orange}{[HCO_3^-][H_3O^+]}} < \underbrace{4.266\times 10^{-7} = 10^{-6.37}}_{\color{red}{[HCO_3^-][H_3O^+]}}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:2.588188em;vertical-align:-1.7240799999999998em;"></span><span class="mord munder"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8641080000000003em;"><span style="top:-1.49398em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight" style="color:orange;"><span class="mopen mtight" style="color:orange;">[</span><span class="mord mathdefault mtight" style="margin-right:0.08125em;color:orange;">H</span><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:orange;">C</span><span class="mord mtight" style="color:orange;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:orange;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8209857142857142em;"><span style="top:-2.188485714285714em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:orange;"><span class="mord mtight" style="color:orange;">3</span></span></span><span style="top:-2.904321428571429em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:orange;"><span class="mbin mtight" style="color:orange;">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.31151428571428574em;"><span></span></span></span></span></span></span><span class="mclose mtight" style="color:orange;">]</span><span class="mopen mtight" style="color:orange;">[</span><span class="mord mtight" style="color:orange;"><span class="mord mathdefault mtight" style="margin-right:0.08125em;color:orange;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.08125em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:orange;"><span class="mord mtight" style="color:orange;">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span><span class="mord mtight" style="color:orange;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:orange;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7026642857142857em;"><span style="top:-2.786em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:orange;"><span class="mbin mtight" style="color:orange;">+</span></span></span></span></span></span></span></span><span class="mclose mtight" style="color:orange;">]</span></span></span></span></span><span style="top:-3em;"><span class="pstrut" style="height:3em;"></span><span class="mord munder"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.864108em;"><span class="svg-align" style="top:-2.26867em;"><span class="pstrut" style="height:3em;"></span><span class="stretchy" style="height:0.548em;min-width:1.6em;"><span class="brace-left" style="height:0.548em;"><svg width="400em" height="0.548em" viewBox="0 0 400000 548" preserveAspectRatio="xMinYMin slice"><path d="M0 6l6-6h17c12.688 0 19.313.3 20 1 4 4 7.313 8.3 10 13
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-331-161C60.687 138.7 32.312 99.3 7 54L0 41V6z"></path></svg></span><span class="brace-center" style="height:0.548em;"><svg width="400em" height="0.548em" viewBox="0 0 400000 548" preserveAspectRatio="xMidYMin slice"><path d="M199572 214
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class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.73133em;"><span></span></span></span></span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:1.7240799999999998em;"><span></span></span></span></span></span><span class="mspace" style="margin-right:0.2777777777777778em;"></span><span class="mrel"><</span><span class="mspace" style="margin-right:0.2777777777777778em;"></span></span><span class="base"><span class="strut" style="height:2.588188em;vertical-align:-1.7240799999999998em;"></span><span class="mord munder"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8641080000000003em;"><span style="top:-1.49398em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight" style="color:red;"><span class="mopen mtight" style="color:red;">[</span><span class="mord mathdefault mtight" style="margin-right:0.08125em;color:red;">H</span><span class="mord mathdefault mtight" style="margin-right:0.07153em;color:red;">C</span><span class="mord mtight" style="color:red;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8209857142857142em;"><span style="top:-2.188485714285714em;margin-left:-0.02778em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span><span style="top:-2.904321428571429em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">−</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.31151428571428574em;"><span></span></span></span></span></span></span><span class="mclose mtight" style="color:red;">]</span><span class="mopen mtight" style="color:red;">[</span><span class="mord mtight" style="color:red;"><span class="mord mathdefault mtight" style="margin-right:0.08125em;color:red;">H</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31731428571428577em;"><span style="top:-2.357em;margin-left:-0.08125em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:red;"><span class="mord mtight" style="color:red;">3</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.143em;"><span></span></span></span></span></span></span><span class="mord mtight" style="color:red;"><span class="mord mathdefault mtight" style="margin-right:0.02778em;color:red;">O</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7026642857142857em;"><span style="top:-2.786em;margin-right:0.07142857142857144em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size3 size1 mtight" style="color:red;"><span class="mbin mtight" style="color:red;">+</span></span></span></span></span></span></span></span><span class="mclose mtight" style="color:red;">]</span></span></span></span></span><span style="top:-3em;"><span class="pstrut" style="height:3em;"></span><span class="mord munder"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.864108em;"><span class="svg-align" style="top:-2.26867em;"><span class="pstrut" style="height:3em;"></span><span class="stretchy" style="height:0.548em;min-width:1.6em;"><span class="brace-left" style="height:0.548em;"><svg width="400em" height="0.548em" viewBox="0 0 400000 548" preserveAspectRatio="xMinYMin slice"><path d="M0 6l6-6h17c12.688 0 19.313.3 20 1 4 4 7.313 8.3 10 13
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0 2 .3 4 1 18.688 2.7 76 4.3 172 5h399450v120H429l-6-1c-124.688-8-235-61.7
-331-161C60.687 138.7 32.312 99.3 7 54L0 41V6z"></path></svg></span><span class="brace-center" style="height:0.548em;"><svg width="400em" height="0.548em" viewBox="0 0 400000 548" preserveAspectRatio="xMidYMin slice"><path d="M199572 214
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<div class="footnotes">
<hr>
<ol>
<li id="fn-1-CzBpDn1V1m">
<p><a href="https://zestedesavoir.com/contenus/beta/2987/les-couples-en-chimie-des-solutions/#principe-de-le-ch%C3%A2telier">Tutoriel qui en parle un peu</a></p>
<a href="#fnref-1-CzBpDn1V1m" class="footnote-backref" title="Retourner au texte de la note 1">↩</a>
</li>
<li id="fn-2-CzBpDn1V1m">
<p><a href="https://zestedesavoir.com/tutoriels/2658/coefficient-de-partage/">Tutoriel qui en parle un peu</a></p>
<a href="#fnref-2-CzBpDn1V1m" class="footnote-backref" title="Retourner au texte de la note 2">↩</a>
</li>
</ol>
</div>Pouvoir tampon d'un acide volatil (CO2), message #1975322019-01-17T23:00:30+01:00nainposteur/@nainposteurhttps://zestedesavoir.com/forums/sujet/11990/pouvoir-tampon-dun-acide-volatil-co2/?page=1#p197532<p>Bonjour, en ce moment en cours je fais l’équilibre acido-basique du corps humains. On a notamment vu qu’il existe deux tampons dans l’organisme : </p>
<p>Un tampon ouvert (de masse variable) correspondant au couple
(CO2)dissous/HCO3- : (CO2)dissous + H2O = (H+) + (HCO3-) . Avec [CO2]d=S*P(CO2) avec P(CO2) la pression partielle en CO2 et S le coeff de solubilité du CO2. </p>
<p>Et un tampon fermé de masse cosntante (en fait plusieurs tampon fermé assimilable a un seul tampon fermé) AH/A- : AH = (A-) + (H+).</p>
<p>Il est dis dans mon cours que pour mesurer le pouvoir tampon total (tampons fermés et tampon ouvert) d’une solution, on peut titrer la solution par apport d’un acide fixe non volatil (par exemple HCl) en maintenant la concentration de CO2 dissous constante par maintien de la pression de CO2 constante au dessus de la solution. Et le tamponnement est effectué soit par consommation des ions HCO3- , soit par titration des ions A- . </p>
<p>Voici ma question : Je ne comprend pas pourquoi on doit maintenir constante la concentration de CO2 dissous pour effectuer le titrage et mesurer le pouvoir tampon total. </p>
<p>Merci d’avance <img src="/static/smileys/smile.png" alt=":)" class="smiley"> </p>pH limite d'existance, message #1217482016-08-26T23:34:41+02:00Coolsinus/@Coolsinushttps://zestedesavoir.com/forums/sujet/6807/ph-limite-dexistance/?page=1#p121748<p>Nan effectivement le fer et les ions hydroxyde ne reagissent pas tant que l'on a pas dépassé la limite de solubilité. En fait j'ai interprété ça comme ça parce que ca me paraît incohérent que la solubilité ne dépende pas des deux espèces impliquées (dans la formation d'un solide) de manière proportionnelle : on voit que la solubilité n'est pas une concentration seuil que les deux espèces dépassent simultanément à coef. stoechiométriques près.</p>
<p>Merci de ton aide</p>pH limite d'existance, message #1217082016-08-26T20:27:20+02:00Goeland-croquant/@Goeland-croquanthttps://zestedesavoir.com/forums/sujet/6807/ph-limite-dexistance/?page=1#p121708<p>Pose toi les bonnes questions : pourquoi considérés tu que la concentration en fer va varier en fonction de la concentraient en soude ? Quel est le principe d'un Ks ?</p>pH limite d'existance, message #1217022016-08-26T20:04:51+02:00Coolsinus/@Coolsinushttps://zestedesavoir.com/forums/sujet/6807/ph-limite-dexistance/?page=1#p121702<p>Bonsoir,</p>
<p>Voici en deux mots l'exercice : </p>
<ul>
<li>
<p>on a une solution de <span>$Fe^{3+}$</span> de concentration <span>$c_0 = 10^{-2} mol.L^{-1}$</span></p>
</li>
<li>
<p>le pH de la solution est fixé par une solution tampon à 1,0</p>
</li>
<li>
<p>on ajoute de la soude et la variation de volume est négligée</p>
</li>
<li>
<p><span>$pK_s(Fe(OH)_3(s)) = 38$</span></p>
</li>
</ul>
<p>Question : déterminer le pH limite d'existence du solide <span>$Fe(OH)_3(s)$</span> </p>
<p>Et la réponse du corrigé donne 2,0, qu'on trouve en considérant qu'à la limite <div class="mathjax-wrapper"><mathjax>$$K_s = [Fe^{3+}][HO^-]^3 = c_0w^3$$</mathjax></div> et on détermine le pH.</p>
<p>Le problème que j'ai c'est qu'on utilise la concentration de <span>$[Fe^{3+}]$</span> à l'état initial, avant d'ajouter de la soude, donc moi j'aurais plutôt posé le problème comme ça, ou <span>$w$</span> est l'avancement à l'équilibre : <div class="mathjax-wrapper"><mathjax>$$K_s = (c_0 - w)w^3$$</mathjax></div>
</p>
<p>Ou bien est-ce que l'on sous-entend que la solubilité <span>$s = w_{eq}$</span> sera bien inférieure à <span>$c_0$</span> et on fait l'approximation <span>$c_0 - w_{eq} = c_0 - s \approx c_0$</span> ?</p>
<p>Quelle est la bonne réponse ?</p>
<p>Coolsinus</p>
<p>(edit Arius pour les tags)</p>Correction d'un exercice non comprise, message #1215212016-08-25T17:42:37+02:00pierre_24/@pierre_24https://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121521<blockquote>
<p>Le <span>$K_A$</span> est précis à ce point ? Donc si au contraire j'ai un <span>$K_A$</span> de <span>$10^{4}$</span>, j'ai <span>$10000$</span> molécules de produit pour <span>$1$</span> seule de réactif à l'équilibre ?</p>
</blockquote>
<p>Probablement pas précis à ce point là (on a quand même que 3 chiffres significatifs, puis faut voir comment ça a été déterminé), mais ça donne une petite idée (voir ci-dessous).</p>
<blockquote>
<p>Le problème c'est que dans l'expression du <span>$K_A$</span> ci-dessus y'a aussi la concentration de <span>$[H_3O^+]$</span> donc je vois pas bien comment cette relation peut être vraie..</p>
</blockquote>
<p>Tout à fait. Mais comme on a pas d'info sur la concentration de <span>$\ce{H2SO4}$</span> au départ, j'ai fait comme si <span>$[\ce{H3O+}]$</span> = 1M, et alors là c'est vrai (c'est triché, mais on est dans un exemple purement hypothétique, donc je fait ce que je veux <img alt="^^" src="/static/smileys/hihi.png"> ). En pratique, tu as tout à fait raison, il faudrait tenir compte de cette concentration <img alt=":)" src="/static/smileys/smile.png"></p>Correction d'un exercice non comprise, message #1215202016-08-25T17:31:11+02:00Coolsinus/@Coolsinushttps://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121520<p>Merci pour ces explications.</p>
<p>J'ai effectivement fait une erreur dans le calcul du <span>$pK_A$</span> de <span>$HSO_4^-$</span>, c'est bien un acide faible.</p>
<p>Le <span>$K_A$</span> est précis à ce point ? Donc si au contraire j'ai un <span>$K_A$</span> de <span>$10^{4}$</span>, j'ai <span>$10000$</span> molécules de produit pour <span>$1$</span> seule de réactif à l'équilibre ?
Le problème c'est que dans l'expression du <span>$K_A$</span> ci-dessus y'a aussi la concentration de <span>$[H_3O^+]$</span> donc je vois pas bien comment cette relation peut être vraie..</p>Correction d'un exercice non comprise, message #1215132016-08-25T15:38:28+02:00pierre_24/@pierre_24https://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121513<p>Bonjour,</p>
<p>Plusieurs choses ici auquel il faut faire attention. La première est qu'effectivement, un acide fort libère la (quasi) totalité de ces H<sup>+</sup> lorsqu'il est en solution. Ça signifie qu'il ne reste plus de <span>$\ce{H2SO4}$</span> en solution, mais <span>$\ce{HSO4-}$</span> et <span>$\ce{H3O+}$</span>. Je te laisse vérifier avec le <span>$K_a$</span> (voir ci-dessous) si tu ne me crois pas, mais tu te rendra compte que c'est très important <img alt=":)" src="/static/smileys/smile.png"></p>
<blockquote>
<p>J'apprends donc qu'un <span>$pK_A$</span> peut être négatif et que <span>$H_3O^+$</span> n'est pas l'acide le plus fort <img alt=":p" src="/static/smileys/langue.png"></p>
</blockquote>
<p>C'est vrai et faux. Comme un acide fort ce dissocie totalement dans l'eau, on considère que dans l'eau, <span>$\ce{H3O+}$</span> est <em>de facto</em> l'acide le plus fort qu'il existe (puisqu'on l'obtient en solution, et pas <span>$\ce{H2SO4}$</span>, par exemple). Ce n'est pas vrai dans un autre solvant <img alt=":)" src="/static/smileys/smile.png"></p>
<blockquote>
<p>J'en conclus que si on précise que c'est un acide fort, il faut comprendre plus fort que <span>$H_3O^+$</span> […]</p>
</blockquote>
<p>Par définition d'un acide fort, oui, c'est un acide avec un <span>$pK_a$</span> plus faible que celui de l'eau, mais c'est vrai <strong>uniquement dans l'eau</strong> (même si c'est le cas la plupart du temps).</p>
<hr>
<p>Pour en revenir à la question de base, je ne suis pas d'accord avec la notation <span>$HSO_4^- + H_2O = SO_4^{2-} + H_3O^+$</span> et en particulier le <span>$=$</span> (que je n'aime en fait pas du tout). Puisque <span>$\ce{HSO4-}$</span> est un acide faible (il possède un <span>$pK_a$</span>), la réaction que tu écrit est un <strong>équilibre</strong>, qui doit s'écrire avec la bonne flèche:</p>
<p>
<div class="mathjax-wrapper"><mathjax>$$\ce{HSO4- + H2O <=> SO4^2- + H3O+}$$</mathjax></div>
</p>
<p>Pourquoi c'est important ? Parce que cette fois, c'est plus une réaction complète (qui serait plus en adéquation avec un <span>$=$</span>), mais un équilibre. Autrement dit, en solution doivent techniquement cohexister <span>$\ce{HSO4-}$</span> et <span>$\ce{SO4^2-}$</span>. Je dit "techniquement", parce qu'il s'agit d'un acide <strong>faible</strong>, et que par définition d'un acide faible, la base conjuguée (<span>$\ce{SO4^2-}$</span>) est présente en très très faible quantité par rapport à celle de l'acide (<span>$\ce{HSO4-}$</span>).</p>
<p>Si tu veux le vérifier, je te rappelle que la définition du <span>$K_a$</span> est </p>
<p>
<div class="mathjax-wrapper"><mathjax>$$\ce{HSO4- + H2O <=> SO4^2- + H3O+} \hspace{2cm} K_a = \frac{[\ce{SO4^2-}][\ce{H3O+}]}{[\ce{HSO4-}]} = 10^{-1,92} \approx 0.012$$</mathjax></div>
</p>
<p>Ce qui signifie que pour 99 molécules de <span>$\ce{HSO4-}$</span> en solution, tu as à peu près une molécule <span>$\ce{SO4^2-}$</span> (et encore, le <span>$pK_a$</span> est relativement faible, en comparaison tu peux essayer avec celui de l'acide acétique, 4.75, et constater que le nombre de molécules d'acétate est encore plus faible).</p>
<p>De facto, en solution, tu as bel et bien, par ordre d'importance: <span>$\ce{H2O}$</span> (le pH à beau être de l'ordre de 1, il y a quand même plus d'eau non protonnée, c'est le solvant !), <span>$\ce{H3O+}$</span> et <span>$\ce{HSO4-}$</span> (et des traces de <span>$\ce{SO4^2-}$</span> et <span>$\ce{H2SO4}$</span>, mais vraiment de manière négligeable par rapport au reste, ce qui explique que ton corrigé n'en parle pas)</p>
<p>Compris ? <img alt=":)" src="/static/smileys/smile.png"></p>Correction d'un exercice non comprise, message #1215092016-08-25T15:08:18+02:00Coolsinus/@Coolsinushttps://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121509<p>En fait on nous donne pas de définition aussi précise que celle de wikipédia, on nous dit simplement qu'un acide fort cède très facilement des protons, donc que la réaction avec l'eau est favorisée, et alors que <span>$K_A$</span> est élevé, donc que <span>$pK_A = -\log_{10} {K_A}$</span> est faible.</p>
<p>J'apprends donc qu'un <span>$pK_A$</span> peut être négatif et que <span>$H_3O^+$</span> n'est pas l'acide le plus fort <img alt=":p" src="/static/smileys/langue.png"></p>
<p>J'en conclus que si on précise que c'est un acide fort, il faut comprendre plus fort que <span>$H_3O^+$</span>, et sinon c'est que c'est moins fort donc que l'acide ne réagit pas avec l'eau avant le titrage ?</p>
<p>Merci de ton aide <img alt=";)" src="/static/smileys/clin.png"></p>Correction d'un exercice non comprise, message #1215052016-08-25T14:25:21+02:00melepe/@melepehttps://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121505<p>Salut,</p>
<p>Je ne me souviens pas de la définition d'acide fort qu'on donne en prépa, mais en lisant sur <a href="https://fr.wikipedia.org/wiki/Acide_fort">wikipedia</a> (qui donne justement l'exemple de <span>$H_2SO_4$</span> : </p>
<blockquote>
<p>De façon plus précise, un acide est dit « fort » lorsque son <span>$pK_a$</span> (liée à la constante d'acidité <span>$K_a$</span> par l'équation <span>$pK_a = -log_{10}K_a$</span>) en solution aqueuse est inférieur à celui du cation hydronium <span>$H_3O^+$</span>, présent naturellement dans l'eau par autoprotolyse, qui vaut <span>$pK_a = -1,7$</span> : au-dessus de cette valeur, les ions hydronium sont de meilleurs donneurs de protons que l'acide, dont une fraction n'est donc pas dissociée, ce qui définit un acide faible ; en dessous de cette valeur, toutes les molécules d'acide sont dissociées, ce qui définit bien un acide fort.</p>
</blockquote>
<p>Donc, ben <span>$HSO_4^-$</span> n'est pas un acide fort. <img alt=":)" src="/static/smileys/smile.png"></p>Correction d'un exercice non comprise, message #1214922016-08-25T12:40:42+02:00Coolsinus/@Coolsinushttps://zestedesavoir.com/forums/sujet/6793/correction-dun-exercice-non-comprise/?page=1#p121492<p>Bonjour,</p>
<p>Dans un exercice de chimie de MPSI, on me dit : </p>
<ul>
<li>
<p>on réalise le titrage d'une solution d'acide sulfurique <span>$H_2SO_4$</span> par de la soude</p>
</li>
<li>
<p><span>$H_2SO_4$</span> est un diacide dont la première acidité est forte</p>
</li>
<li>
<p><span>$pK_A(HSO_4^-/SO_4^{2-}) = 1,9$</span></p>
</li>
</ul>
<p>La question posée est :</p>
<ul>
<li>Quels sont les acides présents, en quantité non négligeables, avant tout ajout de la solution titrante ?</li>
</ul>
<p>Le corrigé dit : </p>
<ul>
<li>La première acidité de <span>$H_2SO_4$</span> étant forte, ie <span>$H_2SO_4$</span> étant un acide fort, celui-ci réagit totalement avec l'eau de la solution aqueuse selon l'équation
<span>$H_2SO_4 + H_2O = HSO_4^-$</span><span>$ + H_3O^+$</span></li>
</ul>
<p>Je suis d'accord, mais le problème est pourquoi, sachant que <span>$pK_A(HSO_4^-/SO_4^{2-}) = 1,9$</span> est faible et donc que <span>$HSO_4^-$</span> est un acide fort, n'a t-on pas <strong>en plus</strong> simultanément <span>$HSO_4^- + H_2O = SO_4^{2-} + H_3O^+$</span> ? De sorte que lorsqu'on ajoute la soude, il ne reste plus que du <span>$SO_4^{2-}$</span>, des ions <span>$H_3O^+$</span> et de l'eau ?</p>
<p>Bonne journée,</p>
<p>Coolsinus</p>