The heat of vaporization of water at 100°C is 40.66 kJ/mol.Calculate the quantity of heat that is absorbed/released when 20.00 g of steam condenses to liquid water at 100°C.

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Quizplus · Accepted Answer

The heat of vaporization is the amount of heat required to convert a liquid into a gas or vice versa at a constant temperature. When steam condenses into water, it releases heat. To find the quantity of heat released, first, convert the mass of water (steam) to moles using the molar mass of water (18.015 g/mol). For 20.00 g of water: $ \frac{20.00 \, \text{g}}{18.015 \, \text{g/mol}} = 1.11 \, \text{mol} $. Then, multiply the moles by the heat of vaporization (40.66 kJ/mol): $ 1.11 \, \text{mol} \times 40.66 \, \text{kJ/mol} = 45.2 \, \text{kJ} $. Since the process is condensation, the heat is released.

The Heat of Vaporization of Water at 100°C Is 40