Question

What is the standard enthalpy change of vaporization of water at 373 K according to the following data:H2(g) + O2(g) → H2O(l)     ΔH° = -285.8 kJ/molH2O(l) → H2O(g)             ΔH° = +40.7 kJ/molNote: The answer should be in units of kJ/mol.

Answer 1

The standard enthalpy change of vaporization of water at 373 K can be found using the given data. We have the following reactions:1  H2 g  + 1/2 O2 g   H2O l      H = -285.8 kJ/mol2  H2O l   H2O g              H = +40.7 kJ/molTo find the enthalpy change of vaporization, we need to consider the second reaction:H2O l   H2O g              H = +40.7 kJ/molThe standard enthalpy change of vaporization of water at 373 K is +40.7 kJ/mol.