Chemistry
posted by Completely Lost .
Calculate the heat released when 25.0 grams of water freezes at 0 degrees celsius.

a) Look up the molar heat (enthalpy) of fusion of water.
b) Convert 25 grams of H2O to moles by dividing by the formula mass of H2O.
c) Multiply (a) times (b) 
GK's method will work but let me save you a step.
The latent heat of fusion of water (the heat released when water turns to ice at 0 C) is 79.8 calories per gram. Many textbooks round it off to 80 cal/g. Multiply 79.8 by 25.0 grams for the answer.