Vapor density compares a gas's density to which reference?

Vapor density compares a gas's density to which reference?

• A. The density of water
• B. The density of air
• C. The density of the liquid
• D. The density of a vacuum

Answer: (B)

Vapor density is the ratio of a gas’s density to the density of air at the same temperature and pressure. This reference to air is what tells you how the gas will behave in the environment. If the vapor density is greater than 1, the gas is heavier than air and may collect in low spots; if it's less than 1, the gas is lighter and will tend to rise. The densities of water, a liquid, or a vacuum aren’t used as the reference for comparing gases in this context.

Vapor density is the ratio of a gas’s density to the density of air at the same temperature and pressure. This reference to air is what tells you how the gas will behave in the environment. If the vapor density is greater than 1, the gas is heavier than air and may collect in low spots; if it's less than 1, the gas is lighter and will tend to rise. The densities of water, a liquid, or a vacuum aren’t used as the reference for comparing gases in this context.