Heat of Vaporization

Heat of vaporization is the amount of heat required to vaporize 1 mole of a liquid at its boiling point.

1)  Calculate the amount of heat necessary to change 36.0 g of water to steam.  (heat of vaporization of H₂O  =  9.70 kcal/mol)

2)  Calculate the heat of vaporization of copper, given the data that 2.0 g of Cu absorbed 2300 cal of heat in changing from a liquid to a gas.

The same amount of heat is given off when a gas condenses or liquifies as is absorbed when the liquid vaporizes.

3) Calculate the amount of heat given off as 14.2 g of Cl₂ gas liquefy.  (Heat of vaporization of Cl₂  =  4.88 kcal/mole)