Which equation should be used to calculate Delta. Hrxn for this reaction? (-393. 5kJ/mol (-285. 83 kJ/mol))-(-1,273. 02 kJ/mol) -1,273. 02 kJ/mol - ((6 mol)(-393. 5 kJ/mol) (6 mol)(-285. 83 kJ/mol)) ((6 mol)(-393. 5 kJ/mol) (6 mol)(-285. 83 kJ/mol)) - (1 mol)(-1,273. 02 kJ/mol).