Question

H2O has a mc021-1.jpgHvap = 40.7 kJ/mol. Solve for the quantity of heat released when 27.9 g of H2O condenses.

A) 60.00 kJ
B) 61.05 kJ
C) 63.09 kJ
D) 68.60 kJ

Answer 1

The heat released for a certain mass of water that is condensing is calculated by multiplying the heat of vaporization and the amount of the substance. Calculation is as follows:

Heat released = (40.7 kJ/mol) (27.9 g) ( 1 mol / 18 g) = 63.09 kJ

Therefore, the correct answer from the choices listed above is option C.