Question

Calculate the standard enthalpy change for the reaction: 2NaOH (s) + H2SO4 (aq) → Na2SO4 (aq) + 2H2O (l)given that the standard enthalpy of formation of Na2SO4 (aq) is -1385 kJ/mol, and the standard enthalpies of formation of NaOH (s), H2SO4 (aq) and H2O (l) are -425 kJ/mol, -814 kJ/mol and -286 kJ/mol respectively.

Answer 1

To calculate the standard enthalpy change for the reaction, we can use the formula:H_reaction =  Hf_products -  Hf_reactantswhere H_reaction is the standard enthalpy change for the reaction, Hf_products are the standard enthalpies of formation of the products, and Hf_reactants are the standard enthalpies of formation of the reactants.For this reaction:H_reaction = [1 *  -1385 kJ/mol  + 2 *  -286 kJ/mol ] - [2 *  -425 kJ/mol  + 1 *  -814 kJ/mol ]H_reaction =  -1385 - 572  -  -850 - 814 H_reaction =  -1957  -  -1664 H_reaction = -293 kJ/molThe standard enthalpy change for the reaction is -293 kJ/mol.