The heat needed to convert 1 lb. of water at 212 F to steam at 212F is?

The heat required to convert 1 pound of water at 212°F to steam at the same temperature (212°F) is known as the latent heat of vaporization. This process does not involve a temperature change; instead, it entails changing the state of the water from liquid to gas, which requires a significant amount of energy due to the breaking of molecular bonds.

The latent heat of vaporization for water is approximately 970.4 BTUs for each pound of water. This value reflects the energy needed to overcome the attractive forces between molecules in the liquid state so that they can enter the gaseous state as steam. This is a critical concept in thermodynamics and is essential for understanding steam systems and heating processes in plant operations.

The other choices do not represent the latent heat of vaporization for water at the specified conditions. For example, the option reflecting 144 BTUs refers to the heat required to raise the temperature of water or is related to specific heat capacity, which applies to heating water rather than converting it to steam. Hence, the correct answer is based on the established latent heat value, confirming the energy needed for this particular phase change.