To calculate the heat released during the combustion of 1 mole of ethane, we can use the balanced chemical equation for the combustion reaction and the given enthalpy values.The balanced chemical equation for the combustion of ethane is:C2H6 + 7/2 O2 2 CO2 + 3 H2OUsing the given enthalpy values, we can calculate the heat released H for the reaction using Hess's Law:H = Hf products - Hf reactants For the products, we have 2 moles of CO2 and 3 moles of H2O:Hf products = 2 * Hf CO2 + 3 * Hf H2O Hf products = 2 * -393.5 kJ/mol + 3 * -285.8 kJ/mol Hf products = -787 kJ + -857.4 kJ Hf products = -1644.4 kJFor the reactants, we have 1 mole of C2H6 and 7/2 moles of O2. Since the enthalpy of formation for an element in its standard state O2 is zero, we only need to consider the enthalpy of combustion for ethane:Hf reactants = Hcomb C2H6 Hf reactants = -1560 kJNow, we can calculate the heat released H for the reaction:H = Hf products - Hf reactants H = -1644.4 kJ - -1560 kJ H = -84.4 kJSo, the heat released when 1 mole of ethane is combusted in oxygen gas to form carbon dioxide and water is -84.4 kJ.