Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: Energy is absorbed in the process of converting a liquid at its boiling point into a gas. As with the melting of a solid, the temperature of a boiling liquid remains constant and the input of energy goes into changing the state. The molar heat of vaporization of a substance is the heat absorbed by one mole of that substance as it is converted from a liquid to a gas. As a gas condenses to a liquid, heat is released. The molar heat of condensation of a substance is the heat released by one mole of that substance as it is converted from a gas to a liquid. Since vaporization and condensation of a given substance are the exact opposite processes, the numerical value of the molar heat of vaporization is the same as the numerical value of the molar heat of condensation, but opposite in sign. In other words, . Answer: gas
[A]: Energy is absorbed in the process of converting a liquid at its boiling point into a what?


[Q]: Passage: Intensity is defined to be the power per unit area carried by a wave. Power is the rate at which energy is transferred by the wave. In equation form, intensity I is. Answer: wave
[A]: Intensity is defined to be the power per unit area carried by a what?


[Q]: Passage: The largest, most complex covalent molecules have thousands of atoms. Examples include proteins and carbohydrates, which are compounds in living things. The smallest, simplest covalent compounds have molecules with just two atoms. An example is hydrogen chloride (HCl). It consists of one hydrogen atom and one chlorine atom, as you can see in the Figure below . You can watch an animation of hydrogen chloride forming at the following URL. Answer: covalent
[A]:
What type of compound is hydrogen chloride?


