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Buffer quiz

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Terms in this set (15)

  • What components make up a buffer solution?
    A buffer solution contains a weak acid and its conjugate base, or a weak base and its conjugate acid.
  • Why do buffer solutions resist drastic changes in pH?
    Buffers resist pH changes by neutralizing added strong acids or bases, keeping H+ and OH- concentrations nearly constant.
  • What happens when a small amount of strong base is added to a buffer?
    The weak acid in the buffer neutralizes the strong base, causing only a slight increase in pH.
  • What happens when a small amount of strong acid is added to a buffer?
    The conjugate base in the buffer neutralizes the strong acid, causing only a slight decrease in pH.
  • What destroys a buffer solution?
    Adding too much strong acid or strong base destroys a buffer; adding water does not affect it.
  • Why does adding water not destroy a buffer?
    Adding water changes the concentrations of both the weak acid and conjugate base proportionally, so their ratio remains the same.
  • What is the ideal ratio of weak acid to conjugate base in a buffer?
    The ideal buffer has equal amounts of weak acid and conjugate base, typically at the half equivalence point.
  • What is the buffer range for a good buffer?
    A good buffer has a weak acid to conjugate base ratio between 10:1 and 1:10.
  • What is buffer capacity?
    Buffer capacity refers to how well a buffer can neutralize added acid or base; higher concentrations of buffer components increase capacity.
  • What are the three ways to make a buffer?
    Buffers can be made by mixing a weak acid with its conjugate base, a weak base with a strong acid (weak base in excess), or a weak acid with a strong base (weak acid in excess).
  • What must be true when making a buffer from a weak base and strong acid?
    The weak base must be present in a higher amount than the strong acid; otherwise, the buffer will be destroyed.
  • What must be true when making a buffer from a weak acid and strong base?
    The weak acid must be present in a higher amount than the strong base; otherwise, the buffer will be destroyed.
  • What equation is used to calculate the pH of a buffer?
    The Henderson-Hasselbalch equation is used: pH = pKa + log([conjugate base]/[weak acid]).
  • What does 'pKa' represent in the Henderson-Hasselbalch equation?
    pKa is the negative logarithm of the acid dissociation constant (Ka) for the weak acid.
  • Can you use moles or molarity in the Henderson-Hasselbalch equation?
    Yes, you can use either moles or molarity for the conjugate base and weak acid, depending on the information given.