When 1 mole of methane burns, the energy released is used to heat water. This illustrates that
- A. energy is created during combustion
- B. energy is destroyed during combustion
- C. energy is transferred from the system to the surroundings but the total remains constant
- D. the enthalpy of the system increases
Explanation
The chemical energy stored in the bonds of methane and oxygen is converted into heat, which passes to the water, so nothing is created or destroyed and the first law holds. The system loses enthalpy, which is why the value is negative, while the surroundings gain the same amount. Every combustion process is an example of this transfer.