A 5.00 g sample of water vapor, initially at 155°C is cooled at atmospheric pressure, producing ice at -55°C. Calculate the amount of heat energy lost by the water sample in this process, in kJ. Use the following data: specific heat capacity of ice is 2.09 J/g.K; specific heat capacity of liquid water is 4.18 J/g.K; specific heat capacity of water vapor is 1.84 J/g.K; heat of fusion of ice is 336 J/g; heat of vaporization of water is 2260 J/g.

Question

Quizplus · Accepted Answer

The heat energy lost involves cooling the vapor to 100°C, condensing it to liquid, cooling the liquid to 0°C, freezing it to ice, and then cooling the ice to -55°C. Calculating each step and summing gives approximately 15.6 kJ.

A 500 G Sample of Water Vapor, Initially at 155°C Is