Question

Calculate the enthalpy change of the following chemical reaction: 2H2 + O2 → 2H2O Given: - ΔHf°(H2O) = -286 kJ/mol - ΔHf°(H2) = 0 kJ/mol - ΔHf°(O2) = 0 kJ/mol

Answer 1

To calculate the enthalpy change  H  of the reaction, we can use the following formula:H =  Hf products  -  Hf reactants For this reaction, the products are 2 moles of H2O, and the reactants are 2 moles of H2 and 1 mole of O2. Using the given standard enthalpies of formation  Hf , we can plug in the values:H = [2   -286 kJ/mol ] - [ 2  0 kJ/mol  +  1  0 kJ/mol ]H =  -572 kJ  -  0 kJ H = -572 kJThe enthalpy change for the reaction is -572 kJ.