That's not how chemistry works. Burning 1 CH4 is not the same as burning 1 C and 2 H2. The formation of carbon dioxide (aka the combustion of carbon) contributes 393.5 kJ per mole of CH4 combusted, and the formation of water (aka the combustion of hydrogen) contributes 483.6 kJ per mole of CH4, the activation energy to split the CH4 molecule is 74.8 kJ per mole of CH4 combusted. So 55% of the heat released per mole is from the hydrogen.
