A solution that contains a weak acid/conjugate base mixture or weak base/conjugate acid mixture.

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Buffer Solutions

• A solution that contains a weak acid/conjugate
  base mixture or weak base/conjugate acid mixture.
• Resists changes in pH when a moderate amount of
  acid or base is added to it
• Made two ways Weak acid and one of its salts OR
  Weak base and one of its salts

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Characteristics of a buffer solution

• pH
• buffer capacity
• amount of acid or base that can be added before
  considerable change to pH
• depends on concentration of acid/conjugate base
  or base/conjugate acid in buffer solution
• if more concentrated, resists changes to pH more
  than a buffer that is more dilute
• Blood has a buffer solution with hydrogen
  carbonate ions and carbonate ions, which is
  important to life

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How does a buffer solution resist changes in pH
with the addition of an acid or a base? Le
Châteliers Principle
4
Acid-Base Titration Curves

• Acid-Base Titration
• Common analytical procedure used to determine
  the concentration of a reactant, using pH, acids,
  bases and indicators
• Equivalence point
• point in a titration when the acid and base that
  are present completely react with each other
• middle of steep rise that occurs in titration
  curve
• If you know volume of both and concentration of
  one, you can find the concentration of the other.

5
Endpoint

• Point in titration where indicator changes colour
• Pick an indicator that changes colour close to
  the equivalence point

6
Strong Acid-Strong Base Titration Curve

• pH 7 at equivalence point
• Use indicators like phenolphthalein, methyl red,
  bromocresol green

7
Weak Acid-Strong Base Titration Curve
pH gt7 at equivalence point Use indicators like
phenolphthalein
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Weak Base-Strong Acid Titration Curve

• pH lt7 at equivalence point
• Use indicators like methyl red, bromocresol
  green

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References

• McGraw-Hill Ryerson Chemistry 12