A student carries out an investigation using four different fuels. The fuels are tested one at a time to increase the temperature of $1\ \text{dm}^3$ of water from $20\degree\text{C}$ to $100\degree\text{C}$. In every case, the fuel burns completely. All the other conditions remain unchanged for each experiment. Which fuel would give the smallest amount of carbon dioxide in these experiments?
- Aethanol, $1367\ \text{kJ mol}^{-1}$
- Bmethane, $890\ \text{kJ mol}^{-1}$
- Cmethanol, $715\ \text{kJ mol}^{-1}$
- Dpropane, $2220\ \text{kJ mol}^{-1}$