How much heat energy (in megajoules) is needed to convert 7 kilograms of ice at –9°c to water at 0°c?
a. 2.48 mj
b. 2.13 mj
c. 3.26 mj
d. 3.09 mj

1.       Energy released from changing the phase of a substance from the liquid phase to solid phase can be calculated by using the specific latent heat of fusion. The heat of fusion of water at 0 degrees Celsius is 334 J/g. Calculation are as follows:

 Energy = 7000 grams x 334 J/g

 Energy = 2338000 J or 2.38 MJ

it is called kinetic energy