Which term describes the gaseous form of a substance that is in a liquid or solid state at normal temperature and pressure?

• A. Aerosols
• B. Vapors
• C. Dusts
• D. Fumes

Answer: (B)

Vapor is the gaseous form of a substance that is normally a liquid or solid at room temperature and pressure. The idea is that at ambient conditions, these substances exist as liquids or solids, but they can transition into a gas—the vapor state. Water vapor, for example, is water in its gaseous form even though water itself is a liquid at room temperature.

Aerosols are suspensions of tiny liquid or solid particles in a gas, not pure gases. Dusts are solid particles suspended in air. Fumes are vapors that originate from condensed solids and are often accompanied by tiny droplets or particles. So the term that best describes the gas phase of substances typically found as liquids or solids at normal conditions is vapor.