How many BTU are needed to change a pound of ice at 32 degrees F to a pound of water at the same temperature?

To convert a pound of ice at 32 degrees Fahrenheit to a pound of water at the same temperature, the process involves melting the ice. The amount of energy required for this phase change is called the latent heat of fusion, which is the energy needed to change a substance from a solid to a liquid at its melting point without changing its temperature.

For ice, the latent heat of fusion is approximately 144 BTUs per pound. Therefore, to melt one pound of ice at 32 degrees Fahrenheit into water at the same temperature, 144 BTUs of energy are required. This is why the option stating 144 BTUs is the correct answer. No temperature change occurs during this process; only the state of the substance changes from solid to liquid, requiring this specific amount of energy to break the intermolecular bonds of the ice structure.