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Chemistry Past Questions and Answers

Topic: Energy changes ∆H accompanying physical and chemical changes

Jamb Chemistry Questions - Energy changes ∆H accompanying physical and chemical changes

Question 1:
When copper (ii) sulphate solution is treated with excess ammonium hydroxide, a precipitate is first formed, and then this dissolves to give a deep blue solution. This deep blue solution is a
  • A Cu(OH)<sub style='font-size: smaller;'>2</sub>
  • B CuSo<sub style='font-size: smaller;'>4</sub>.5H<sub style='font-size: smaller;'>2</sub>O
  • C (NH<sub style='font-size: smaller;'>4</sub>)<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • D Cu(NH<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>4</sub>(OH)<sub style='font-size: smaller;'>2</sub>
  • E CuSO<sub style='font-size: smaller;'>4</sub>.(NH<sub style='font-size: smaller;'>4</sub>)<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>.2H<sub style='font-size: smaller;'>2</sub>O
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Question 2:
The number of grammes of potassium hydroxide in 250cm3 of one molar solution is?
(K = 39, O = 16, H = 1)
  • A 40g
  • B 52g
  • C 100g
  • D 26g
  • E 14g
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Question 3:
The hydroxyl ion concentrated, (OH-), in a solution of sodium hydroxide of pH 10.0 is?
  • A 10<sup style='font-size: smaller;'>-10</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • B 10<sup style='font-size: smaller;'>-6</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • C 10<sup style='font-size: smaller;'>-4</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • D 10<sup style='font-size: smaller;'>-2</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
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Question 4:
Hydration of ions in solution is associated with
  • A Absorption of heat
  • B Reduction of heat
  • C Conduction of heat
  • D Liberation of heat
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