Four reactions are performed in identical insulated beakers

CHEMISTRY · Subjective · A Level · Chemistry · Energetics · Energetics

Problem

Four reactions are performed in identical insulated beakers, each containing 100.0 g100.0\,\text{g} of water at 25 ∘C25\,^{\circ}\text{C}. The measured molar enthalpies are: Reaction A: ΔH=−55 kJ mol−1\Delta H = -55\,\text{kJ mol}^{-1} Reaction B: ΔH=+23 kJ mol−1\Delta H = +23\,\text{kJ mol}^{-1} Reaction C: ΔH=−12 kJ mol−1\Delta H = -12\,\text{kJ mol}^{-1} Reaction D: ΔH=+87 kJ mol−1\Delta H = +87\,\text{kJ mol}^{-1} Assuming equal amounts (in moles) of reactant are used in each case, identify which reaction will result in the largest temperature increase of the surrounding water.

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