1. The problem statement, all variables and given/known data I have the following task: The Standard enthalpy of formation of gaseous H2O at 298K is -241.82 kJ mol-1. Estimate its value at 100 °C given the following values of the molar heat capacities at constant pressure: H2O (g): 33.58 JK-1mol-1, H2 (g): 28.84 JK-1mol-1, O2 (g): 29.37 JK-1mol-1. Assume that the heat capacities are independent of temperature. 2. Relevant equations 3. The attempt at a solution The only formula I can think of is this one: But I don't know how to calculate this exactly. Can some help me getting started?