Question

The heat of combustion of ethane and benzene is $-1560$ and $-3268 \,kj\, mol^{-1}$ respectively. Which of two has higher efficiency as fuel per gram and the amount of heat produced per gram?

• A. Benzene, $41.9\, kj\, g^{-1}$
• B. Ethane, $52 \,kj\, g^{-1}$
• C. Benzene, $78 \,kj\, g^{-1}$
• D. Ethane, $30 \,kj\,g^{-1}$

Answer 1

Answer: (B)

Heat produced by ethane $= \frac{1560}{30} = 52\,kJ\,g^{-1}$
Heat produced by benzene $= \frac{3268}{78}= 41.9\,kJ\,g^{-1}$