Compounds like CCl2F2 are known as chlorofluorocarbons, or CFCs. These compounds were once widely used as refrigerants but are now being replaced by compounds that are believed to be less harmful to the environment. The heat of vaporization of CCl2F2 is 289 j/g. What mass of this substance must evaporate to freeze 200 g of water initially at 15 oC? (The heat of fusion of water is 334 j/g; the specific heat of water is 4.18 j/g - k.)