Using the standard enthalpies of formation given below (kJ mol−1), calculate the standard enthalpy change for each methanol-synthesis route at 298 K and state which route is more exothermic.
Data: CO2(g) = –394, CO(g) = –111, H2(g) = 0, CH3OH(l) = –239, H2O(l) = –286.
Route A: CO2(g) + 3 H2(g) → CH3OH(l) + H2O(l)
Route B: CO(g) + 2 H2(g) → CH3OH(l)