Q. To help prevent frost damage, fruit growers sometimes protect their crop by spraying it with water when overnight temperatures are expected to go below the freezing mark. When the water turns to ice during the night, heat is free into the plants, thereby giving them a measure of protection against the falling temperature. Assume a grower sprays 7.64 kg of water at 0°C onto a fruit tree.
(i) How much heat is released by the water when it freezes?
(ii) How much temperature of 175kg tree rise would if it absorbed the heat release in part (i)? Presume that the specific heat capacity of the tree is 2.5 x 103 J/(kg C°) and that no phase change occurs within the tree itself.