Question

when 32.4 g of water vapor condenses, how much heat is given off? The heat of vaporization for water is 40.67 kj/mol

Answer 1

When a water vapor condenses, heat is being released from the process. This heat is called latent heat of vaporization since the phase change happens without any change in the temperature. This value is constant per mole of a substance as a function of pressure and temperature. For this problem, we are given the heat of vaporization at a certain T and P. We use this value to calculate the total heat released from the process. We calculate as follows:

Total heat released: 32.4 g ( 1 mol / 18.02 g ) (40.67 kJ / mol) = 73.12 kJ

Therefore, 73.12 kJ of heat is released from the condensation of 32.4 g of water vapor.