Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

The enthalpy changes for two reactions are given below. $\text{K}_2\text{CO}_3(s) + 2\text{HCl}(aq) \rightarrow 2\text{KCl}(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g) \quad \Delta H = -34.0\,\text{kJ mol}^{-1}$ $\text{KHCO}_3(s) + \text{HCl}(aq) \rightarrow \text{KCl}(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g) \quad \Delta H = +32.8\,\text{kJ mol}^{-1}$ Determine the enthalpy change for the reaction shown below. $2\text{KHCO}_3(s) \rightarrow \text{K}_2\text{CO}_3(s) + \text{H}_2\text{O}(l) + \text{CO}_2(g)$

  • A$-31.6\,\text{kJ mol}^{-1}$
  • B$1.2\,\text{kJ mol}^{-1}$
  • C$66.8\,\text{kJ mol}^{-1}$
  • D$99.6\,\text{kJ mol}^{-1}$

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