Gas Heat ESCO Practice Exam

Which of the following statements is true of nitrogen?

1. It enhances combustion efficiency by facilitating heat transfer

2. It has no effect on combustion

3. It reduces combustion efficiency by absorbing heat

4. It increases the rate of combustion

The correct answer is: It reduces combustion efficiency by absorbing heat

Nitrogen is an inert gas that makes up a large percentage of the air we breathe. In the context of combustion, when nitrogen is present in the combustion air, it can act as a heat sink and absorb some of the heat released during the combustion process. This absorption of heat by nitrogen reduces the overall combustion temperature, which in turn can lead to a decrease in combustion efficiency. Therefore, the statement that nitrogen reduces combustion efficiency by absorbing heat is correct. Option A is incorrect because nitrogen does not enhance combustion efficiency by facilitating heat transfer; instead, it has a cooling effect on the combustion process. Option B is incorrect as nitrogen does have an effect on combustion, as explained above. Option D is incorrect because nitrogen does not increase the rate of combustion; in fact, it can have the opposite effect by reducing the combustion temperature.