The bomb calorimeter is an instrument used to measure the heat of reaction at a fixed volume and the measured heat which is called the change of internal energy.
By combustion of 1 mole
C2H6(ΔU)=−massHeatcapacity×ΔT×Molarmass=−0.320×0.5×30=−1000kJ
C2H6(g)+7/2O2(g)→2CO2(g)+3H2O(l)
Δng=2−(2+7/2)=−(7/2)
ΔH=ΔU+ΔnRT
=−1000−7/2×8.3×300kJ
=−1000−6.225
=−1006kJ
So heat released =1006kJmol−1