Latent heat of vaporization refers to the heat exchanged when a substance changes state between which phases?

Get ready for the NCEA Level 1 Energy Test. Utilize flashcards and multiple choice questions with clear explanations and hints. Prepare for success!

Multiple Choice

Latent heat of vaporization refers to the heat exchanged when a substance changes state between which phases?

Latent heat of vaporization is the energy involved when a substance changes between liquid and gas. This energy is required to overcome the forces holding the liquid together so that molecules can escape into the gas phase. Importantly, during this change the temperature stays the same, even as heat is added, because the energy goes into changing the state rather than raising temperature. So, the correct idea is liquid to gas (and the reverse gas to liquid during condensation). The other scenarios describe energy changes for solid to liquid (fusion) or for heating without a phase change (just raising temperature), or for a gas to solid transition, which is not what vaporization refers to.

Latent heat of vaporization is the energy involved when a substance changes between liquid and gas. This energy is required to overcome the forces holding the liquid together so that molecules can escape into the gas phase. Importantly, during this change the temperature stays the same, even as heat is added, because the energy goes into changing the state rather than raising temperature.

So, the correct idea is liquid to gas (and the reverse gas to liquid during condensation). The other scenarios describe energy changes for solid to liquid (fusion) or for heating without a phase change (just raising temperature), or for a gas to solid transition, which is not what vaporization refers to.

More practice questions