When `100 c.c.` of a mixture of methane `(CH_(4))` and ethylene `(C_(2)H_(4))` was exploded with an excess of oxygen , the volume of carbon dioxide produced `(` measured at the same temperature and pressure `)` was `160 c.c.` Calculate the heat evolved when `22.4` litre of the mixture of methane and ethylene `(` measured at `N.T.P. )` is completely oxidised to carbon dioxide and water at constant volume.
`CH_(4)+2O_(2)=CO_(2)+2H_(2)O+212000cal,`
`C_(2)H_(4)+3O_(2)=2CO_(2)+2H_(2)O+333000 cal.`