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8 Cards in this Set
- Front
- Back
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What is a buffer? |
A solution that resists change in pH by neutralizing any acid or base that is added. Created by mixing a solution of a weak acid with a solution of its conjugate base. |
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How do buffers work? |
They work by applying Le Chateliers principle to a weak acid equilibrium. They contain significant amounts of the weak acid as well as significant amounts of the conjugate base. The acid molecules react with the added base to neutralize and the base molecules react with the added acid to neutralize. The equilibrium then shifts to recover any lost product or reactant. |
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What is the Henderson-Hasselbalch equation |
It is an equation that calculates the pH of a buffer. pH= pKa + log[base anion/weak acid] |
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What is the buffering capacity? |
The amount of acid or base that a buffer can neutralize. The buffering capacity increases with increasing absolute concentration of the buffering components. |
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What is the buffering range? |
The pH range that the buffer can be effective. |
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What make for an effective buffer? |
When there are equal concentrations of acid and base. And when the concentrations are large. A buffer will still be effective as long as the ratio of base to acid is between 0.1 and 10. The effective range of a buffer is pKa plus or minus 1. |
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What happens in an acid base titration? (end point, equivalence point) |
A solution of an unknown concentration (titrant) is slowly added to the solution of a known concentration until the reaction is complete. Endpoint signifies the end of the reaction. An indicator may be added to determine the endpoint. when the moles of H3O are equal to moles of OH- the titration has reached the equivalence point. |
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When titrating with an indicator, how do you determine the endpoint? |
The Pka of the H-indicator, is approximately pH at the equivalence point. |
