Heat released by 0.025 mol of H3PO4 = 525 J Heat released by 2 moles of H3PO4 = 2/0.025 x 525 = 42000 J Hrxn = - heat released by 2 moles of H3PO4 = -42000 J = -42 kJ Solution Heat released by 0.025 mol of H3PO4 = 525 J Heat released by 2 moles of H3PO4 = 2/0.025 x 525 = 42000 J Hrxn = - heat released by 2 moles of H3PO4 = -42000 J = -42 kJ.