`1.00litre` sample of a mixture of `CH_(4(g))` and `O_(2(g))` measured at `25^(@)C` and `740 t or r` was allowed to react at constant pressure in a calorimeter which together with its contents had a heat capacity of `1260cal//K`. The complete combustion of the methane to`CO_(2)` and `H_(2)O` caused a temperature rise in the calorimeter of `0.667K`. What was the mole per cent of `CH_(4)` in the original mixture ?
`(DeltaH_(comb.)^(@)(CH_(4))=-215kcal mol^(-1))`

Answer

`9.75%;`