Hydrogen(285)
Divide 285 by the molar mass of Hydrogen which is 1.008
(kj/mol)/(grams/mols)= Kj(mols)/(grams x mols)
It gives you 282.738 kJ/g
For Propane(2220) C3H8 - MM is 44.094
Divide 2220 by 44.094
Gives you 50.347 kJ/g which if you round it off to 2 decimal places it is the same as...