To calculate the enthalpy change H for the ionization of a hydrogen atom, we can use the given ionization energy. Ionization energy is the energy required to remove an electron from an atom or ion in its gaseous state. In this case, the ionization energy is given as 1312 kJ/mol.For the ionization of a hydrogen atom, the reaction can be represented as:H g H+ g + e-Since the ionization energy is the energy required for this process, the enthalpy change H for the reaction is equal to the ionization energy:H = 1312 kJ/molTherefore, the enthalpy change for the ionization of a hydrogen atom is 1312 kJ/mol.