Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

50 cm$^3$ of 2.50 mol dm$^{-3}$ hydrochloric acid was put into a polystyrene beaker with negligible heat capacity. The temperature was measured and then 50 cm$^3$ of 2.50 mol dm$^{-3}$ NaOH, initially at the same temperature, was rapidly added while stirring. The temperature increased by 17 ^{\circ}C. The final solution can be taken to have a specific heat capacity of 4.2 J g$^{-1}$ K$^{-1}$. What is an approximate value for the molar enthalpy change of neutralisation of hydrochloric acid and sodium hydroxide from this experiment?

  • A$-\dfrac{(50 \times 4.2 \times 17)}{(0.050 \times 2.5)}\text{ J mol}^{-1}$
  • B$-\dfrac{(50 \times 4.2 \times 17)}{(0.10 \times 2.5)}\text{ J mol}^{-1}$
  • C$-\dfrac{(100 \times 4.2 \times 17)}{(0.050 \times 2.5)}\text{ J mol}^{-1}$
  • D$-\dfrac{(100 \times 4.2 \times 17)}{(50 \times 2.5)}\text{ J mol}^{-1}$

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