Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

Use the information below to answer this question. $\Delta H_f^\circ(\text{P}_4\text{O}_{10}(s)) = -3012\ \text{kJ mol}^{-1}$ $\Delta H_f^\circ(\text{H}_2\text{O}(l)) = -286\ \text{kJ mol}^{-1}$ $\Delta H_f^\circ(\text{H}_3\text{PO}_4(s)) = -1279\ \text{kJ mol}^{-1}$ What is $\Delta H^\circ$ for the reaction displayed? $\text{P}_4\text{O}_{10}(s) + 6\text{H}_2\text{O}(l) \rightarrow 4\text{H}_3\text{PO}_4(s)$

  • A$-9844\ \text{kJ mol}^{-1}$
  • B$-388\ \text{kJ mol}^{-1}$
  • C$-97\ \text{kJ mol}^{-1}$
  • D$+2019\ \text{kJ mol}^{-1}$

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