1. Changes of State and Latent Heat

2. Changes of state for water

3. Latent heat of Fusion (L f ): is the amount of heat required/released per unit of mass to melt a solid/freeze a liquid. Latent heat of Vapourization (L v ): is the amount of heat required/released per unit of mass to vapourize a liquid/condensate a gas. where E H is the heat in joules and m is the mass in kilograms. L f, L V are measured in joules per kilogram (J/kg).

4. Table 8.5 lists the latent heats of fusion and vapourization for some common substances.

5. Ex. One danger of leaving a tea kettle unattended on the stove is having it boil dry. How much heat is required to change 0.20 kg of water (about the amount for a good cup of tea) from room temperature of 20ºC to vapour? Calculate the cost if electricity in Ontario cost around $0.12 kW.h. [5.3 x 10 5 J, $0.02]

6. What would be the total amount of energy released in cooling 3.00 kg of nitrogen gas at room temperature, 20.0ºC to liquid nitrogen at -201ºC?  c N-gas = 1.04x10 3 J/kg o C; c N-liquid = 1.10x10 3 J/kg o C