How many BTUs are required to change one pound of water into one pound of steam?

To transform one pound of water into one pound of steam, a specific amount of energy, measured in British Thermal Units (BTUs), is required. This energy accounts for the latent heat of vaporization, which is the energy needed to turn water at its boiling point into steam without changing its temperature.

The latent heat of vaporization for water is approximately 970.3 BTUs per pound. This means that when water reaches 212°F (the boiling point at standard atmospheric pressure), it requires 970.3 BTUs to convert it into steam at the same temperature. This process is crucial in various applications, such as heating systems, power generation, and industrial processes where phase changes occur.

Consequently, the correct choice reflects the known energy requirement for this phase change, making it the accurate answer in the context of steam generation. Other numbers provided in the multiple-choice options do not correspond to the actual latent heat of vaporization for water at standard conditions.