To calculate the enthalpy change of isomerization for butene-1 to butene-2, we can use the following formula:H_isomerization = H_f butene-2 - H_f butene-1 Where:H_isomerization = enthalpy change of isomerizationH_f butene-1 = standard enthalpy of formation for butene-1H_f butene-2 = standard enthalpy of formation for butene-2Plugging in the given values:H_isomerization = -25.8 kJ/mol - -24.7 kJ/mol H_isomerization = -1.1 kJ/molThe enthalpy change of isomerization for butene-1 to butene-2 is -1.1 kJ/mol.