Minnesota Boiler License Practice Exam

What happens to the latent heat of steam when pressure is increased?

1. It increases

2. It decreases

3. It remains constant

4. It fluctuates

The correct answer is: It decreases

When the pressure of steam is increased, the latent heat of vaporization decreases. Latent heat is the amount of heat required for a substance to change its phase from liquid to gas without changing its temperature. As pressure increases, the boiling point of water also rises, which means that steam becomes more compact, and the energy required to create the phase change from liquid to vapor diminishes. This relationship between pressure and latent heat is an important concept in thermodynamics, particularly in the operation of boilers and steam systems. As the pressure in a boiler increases, the heat energy required to convert water into steam at that higher pressure is less, resulting in a lower latent heat. Understanding this relationship is crucial for effective boiler operation and efficiency management. Therefore, as you correctly identified, increasing the pressure leads to a decrease in the latent heat of steam.