Final answer:
The heat per pound needed to change the temperature of water is not the same in all states because specific and latent heats vary for different phases. The specific heat applies to temperature changes within a phase, while latent heat is involved during phase changes without temperature changes.
Step-by-step explanation:
The heat per pound needed to change the temperature of water is not the same across all phases of water. This concept is rooted in the specific heat and latent heat properties of substances. The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius and it varies for water in different states.
In the liquid state, the specific heat of water is about 4.18 J/g°C, allowing for straightforward temperature changes without a phase change. However, when water changes from liquid to gas (vaporization) or from solid to liquid (melting), the process requires a different type of heat called latent heat. Latent heat is the energy absorbed or released by a substance during a phase change without changing the temperature. Specifically, the heat of vaporization of water is about 2,250 J per gram, indicating the substantial energy required to convert liquid water into vapor, due to the need to overcome strong intermolecular forces.
Therefore, the heat required to change the temperature of water depends on its phase, and the correct answer to the question is 2) False.