Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Kaleyrvt on January 16, 2007, 08:56:23 PM
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Buffer solutions have the unique ability to resist changes in pH when an acid or base is added to them. One impotant buffer system that helps to maintain blood pH at a constant value of 7.4 is the hydrogen phosphate buffer. The chemical equation for this buffer system is: H2PO4-(aq) + H2O <--> H3O+(aq) HPO4 2-
Use Le Chatleier’s principle to explain why the pH of a hydrogen phoosphate buffer system remains constant when:
a) small amounts of acid are added
b) small amoutns of base are added
In what I have read, adding small amount of either will do nothing-however, this question is worth 10 marks thus I don't know what to look at then....Any tips or website suggestions?
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If you add acid to a buffer, what will be the predominant reaction? If you add base to a buffer, what will be the predominant reaction?
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OK GUYS....This is the answer I cam up with to my original question. Can someone please go over it to see if it makes ANY sense???! I hope this is ok---please tell me honestly though!
A buffer solution is a solution that resists slight changes in pH when H3O+, hydronium ions, or OH-, hydroxide ions are added. Buffers are prepared by mixing a weak acid with its salt (conjugate base) or a weak base and its salt (conjugate acid).
A buffer solution is an eqiullibrium system that, because it contains a weak acid and a weak base, can react with both addedacids and bases to maintain a constant pH level.
Acocording to le chateliers principle, if an acid is added to a buffer solution, the H3O+ concentration will increase, and the equillibirum will shift to the left to adjust the stress. The added H3O+ reacts with the base of the buffer system and is consumed by that base, causing little to no change in the pH.
If a base is added to a buffer system, the equilibrium shifts to the left, casuing a decrease in the OH_ concentration. The OH- is neutralized by the the acid of the buffer system, again causing very little change in the pH. This explains why buffer systems are important in maintaining the pH of your blood at a necessary pH of 7.4 in your body.
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Anybody have any opinions on my answer??
Any feed back would be great!
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OK GUYS....This is the answer I cam up with to my original question. Can someone please go over it to see if it makes ANY sense???! I hope this is ok---please tell me honestly though!
A buffer solution is a solution that resists slight changes in pH when H3O+, hydronium ions, or OH-, hydroxide ions are added. Buffers are prepared by mixing a weak acid with its salt (conjugate base) or a weak base and its salt (conjugate acid).
A buffer solution is an eqiullibrium system that, because it contains a weak acid and a weak base, can react with both addedacids and bases to maintain a constant pH level.
Acocording to le chateliers principle, if an acid is added to a buffer solution, the H3O+ concentration will increase, and the equillibirum will shift to the left to adjust the stress. The added H3O+ reacts with the base of the buffer system and is consumed by that base, causing little to no change in the pH.
If a base is added to a buffer system, the equilibrium shifts to the left, casuing a decrease in the OH_ concentration. The OH- is neutralized by the the acid of the buffer system, again causing very little change in the pH. This explains why buffer systems are important in maintaining the pH of your blood at a necessary pH of 7.4 in your body.
Excellent explanation.
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thanks a bunch!!!!
You guys are all awesome!! ;)