42. Solving a chemistry problem

4. In a calorimetric bomb, 1 g of oxalic acid H2C2O4 was burned at 25°C. At the same time, 2840 J of heat was released. The heats of formation of water and carbon dioxide from the elements under the same conditions are respectively -285.8 and -393.5 kJ/mol. Calculate the enthalpy of combustion and the enthalpy of formation of oxalic acid under standard conditions.