How much heat would be released by the condensation of 5.40 g of steam at 100°C and the subsequent cooling of the water to 25°C? [ΔHvap = 40.7 kJ/mol at 100°C; Cp for H₂O(l) is 4.18 J g-1 °C-1]

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Quizplus · Accepted Answer

First, calculate the moles of steam: 5.40 g / 18.015 g/mol = 0.2998 mol. The heat released during condensation is 0.2998 mol * 40.7 kJ/mol = 12.2 kJ. Then, calculate the heat released when cooling the water: 5.40 g * 4.18 J/g°C * (100°C - 25°C) = 1.69 kJ. Total heat released = 12.2 kJ + 1.69 kJ = 13.9 kJ.

How Much Heat Would Be Released by the Condensation of 5.40