Orange growers in Florida spray their crops with water if there is a threat of freezing. Explain how this procedure could provide enough heat to save their crops. 1. a) Which latent heat value, fusion or vapourization, is larger for any given substance? b) Use the kinetic molecular theory to explain what is going on at the molecular level during these two changes of state. 2. How much heat does a freezer remove from 0.25 kg of water in an ice cube tray if the temperature of the water is On C? 3. A 0.54 kg sample of material requires 1.782 X 105] of energy to melt it. What is the latent heat of fusion for this material? 4. A tank containing 740 kg of water cools from 15 C to 0' C and com- pletely freezes. How many hours would a 1.2 kW electric heater have to work to provide the equivalent heat the water gives off? (The heater provides 1.2 X 103 J/s of heat.)