Minnesota Boiler License Practice Exam

Which of the following statements about steam and water is correct?

1. Steam has higher latent heat than water

2. Water has more total heat than steam

3. Both have the same total heat at the same temperature

4. Steam cannot absorb latent heat

The correct answer is: Steam has higher latent heat than water

The statement that steam has higher latent heat than water is accurate. Latent heat refers to the amount of energy absorbed or released by a substance during a phase change without a change in temperature. Specifically, steam, when it condenses back into water, releases a significant amount of latent heat. This energy is crucial in various applications, including heating and power generation, as it can be harnessed for doing work or raising temperatures in other systems. In contrast, the other options can be clarified: water does not possess more total heat than steam when considering the same mass at a specific temperature; rather, steam generally has more energy content when including the latent heat of vaporization in its calculations. The total heat of substances at the same temperature is not the same because steam contains additional energy associated with its phase in the gaseous state. Finally, steam can indeed absorb latent heat during the process of vaporization, making it capable of absorbing energy without changing its temperature. These distinctions are vital for understanding thermal dynamics in boiler operations and energy systems.