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2 marksTitrimetric (Volumetric) Methods of Analysis

CAPE Chemistry Unit 2 · 2007 · Paper 2 · Question 4(c)(i)(a)

The carbonic acid-bicarbonate buffer system controls blood pH according to: CO2(aq) + H2O(l) <=> H2CO3(aq) (Equation 1) and H2CO3(aq) <=> H+(aq) + HCO3-(aq) (Equation 2).

During periods of strenuous exercise, carbon dioxide builds up in the blood. Explain the effect of this build-up on the buffer system with reference to Equations 1 and 2.

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Other parts of this question

  1. 4(a)Define the term 'buffer solution'.[2 marks]
  2. 4(b)(i)Explain how a buffer mixture of a weak acid and its salt maintains pH upon the addition of strong acid.[3 marks]
  3. 4(b)(ii)Explain how a buffer mixture of a weak acid and its salt maintains pH upon the addition of strong alkali.[3 marks]
  4. 4(c)(i)(b)Explain how breathing more deeply and quickly during exercise can reverse this effect.[4 marks]
  5. 4(d)(i)Write the expression for K_a of ethanoic acid.[1 mark]
  6. 4(d)(ii)Use the K_a expression to calculate the pH of the buffer solution.[5 marks]

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