Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

Slaked lime, $\text{Ca(OH)}_2$, can be produced starting from limestone, $\text{CaCO}_3$. When limestone is heated in a lime kiln at $1000^\circ\text{C}$, it breaks down according to the equation below. reaction 1: $\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)$ Water is then added to calcium oxide, $\text{CaO}$, in the reaction shown below. reaction 2: $\text{CaO}(s) + \text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(s)$ What are the enthalpy changes of these reactions?

  • Areaction 1 endothermic; reaction 2 endothermic
  • Breaction 1 endothermic; reaction 2 exothermic
  • Creaction 1 exothermic; reaction 2 endothermic
  • Dreaction 1 exothermic; reaction 2 exothermic

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