freon is a collant used in refrigerators and freezers. its heat of vaporization is 289 J/g. what mass of freon must be evaporated to freeze 450 g of water, initially at 20C, in making ice cubes?

Question

freon is a collant used in refrigerators and freezers. its heat of vaporization is 289 J/g. what  mass of freon must be evaporated to freeze 450 g of water, initially at 20C, in making ice cubes?

anonymous · Answer

$$450g*(4.184 J/gC) *-20C = 37656 J$$

First, we see how many joules are needed to freeze 450 g of water, using the specific heat capacity of water. Then, we simply use the heat of vaporization to convert from joules to grams of freon.

$$37656J*(1g/289J) = 130.298g$$