Quelpr
3 marksSolubility Product

CAPE Chemistry Unit 1 · May/June 2025 · Paper 2 · Question 2(b)(ii)

Definitions related to solubility equilibrium.

Calcium phosphate, Ca3(PO4)2, is a water-insoluble mineral used to make commercial fertilizers. Given that the concentrations of Ca2+ and PO4^3- ions in equilibrium are 2 × 10^-8 and 1 × 10^-9 respectively, determine the solubility product, Ksp, of calcium phosphate.

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  1. 2(a)(i)Describe the FOUR characteristic features of this dynamic equilibrium.[4 marks]
  2. 2(a)(ii)Write a balanced chemical equation to represent the reaction described in 2(a) above.[2 marks]
  3. 2(a)(iii)Calculate the Kp value of the equilibrium mixture.[3 marks]
  4. 2(b)(i)Describe EACH of the following terms: Solubility product [2 marks] Common ion effect [2 marks][4 marks]
  5. 2(b)(iii)Write a balanced equation for the equilibrium reaction of the formation of calcium and phosphate ions from calcium phosphate.[2 marks]
  6. 2(c)Comment on the solubility of silver chloride in water compared with the solubility of silver chloride in dilute hydrochloric acid and justify the difference,…[2 marks]
  7. 2(d)Write the steps in an experimental procedure for the determination of the solubility product constant of barium hydroxide, Ba(OH)2.[5 marks]
  8. 2(e)(i)Define the term 'buffer solution'.[1 mark]
  9. 2(e)(ii)Explain how the molecular structure of amino acids relates to their function as buffer solutions in human blood.[3 marks]
  10. 2(e)(iii)State ONE industry in which buffer solutions are used.[1 mark]

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