Calculate the enthalpy of CH, formation AH, from the elements: C(graphite) + 2H2(g) = CH,(g) %3D If we know the enthalpy of the following reactions: Reaction 1: Caraphite) + O2(g) = CO,(g) Reaction 2: H,(g) + 02(g) = H,0(c) AH, = - 393 kJ %3D AH, = - 285 kJ Reaction 3: CH,(g) + 20,(g) = CO,(g) + 2H,0(c) AH; = - 890 kJ