Calculate the heat of formation of H2O (l) at 90oC from the heat of formation at 25OC.

H2(g) + O2(g) ---- H2O (l) H = -68,370 cal

The average values of the heat capacities calculated are:

Cp (H2) = 6.90 cal mol-deg

Cp (O2) = 7.05 cal/mol-deg

Cp (H2O) = 18 cal/mol-deg