Question
The combustion enthalpies of carbon, hydrogen, and methane are -395.5 kJ mol^{-1}, -284.8 kJ mol^{-1} and -890.4 kJ mol^{-1} respectively at 25^0C. The value of s†an dard formation enthalpies of methane at that temperature is (1) 890.4 kJ mol^{-1} (2)-298.8 kJ mol^{-1} (3) -74.7 kJ mol^{-1} (4) -107.7 kJ mol^{-1}