Final answer:
Water vapor is formed when thermal energy is transferred to water, causing a temperature change and changing water from liquid to gas through vaporization. The energy for phase changes can be calculated using the formula Q = mLy, where m is mass and Ly is the latent heat of vaporization. Water requires a high amount of heat energy for this transition due to its high heat of vaporization.
Step-by-step explanation:
Water vapor is formed when thermal energy, or heat energy, is transferred to a liquid such as water, which causes a temperature change and a change of state from liquid to gas. This process is known as vaporization. When water gains enough thermal energy, its molecules begin to move faster and eventually break the hydrogen bonds holding them together; as a result, they escape into the air as water vapor. When thermal energy is transferred to the surroundings during condensation, water vapor turns back to liquid, which can warm the surroundings due to the release of the latent heat it initially absorbed during vaporization.
To calculate the energy required for these phase changes, we use the formula Q = mLy, where Q is the heat energy, m is the mass of the substance, and Ly is the latent heat of vaporization. The latent heat is the amount of heat needed to convert a substance to a gas without a change in temperature. Particularly for water, there is a high heat of vaporization, meaning a significant amount of energy is required to convert water into water vapor.