How does a liquid's density compare to a gas's density under the same conditions?

How does a liquid's density compare to a gas's density under the same conditions?

• A. Liquids are far denser than gases under the same conditions.
• B. Gases are far denser than liquids under the same conditions.
• C. They have the same density under the same conditions.
• D. Density cannot be compared across phases.

Answer: (A)

Density is mass per volume. At the same temperature and pressure, the particles in a liquid sit much closer together than in a gas, so a given volume of liquid contains far more mass than the same volume of gas. Gases fill the space and are highly compressible, giving them a much lower density. Therefore liquids are far denser than gases under the same conditions. Density can be compared across phases, and the idea that they have the same density or that density cannot be compared would miss how tightly packed the particles are in each phase.

Density is mass per volume. At the same temperature and pressure, the particles in a liquid sit much closer together than in a gas, so a given volume of liquid contains far more mass than the same volume of gas. Gases fill the space and are highly compressible, giving them a much lower density. Therefore liquids are far denser than gases under the same conditions. Density can be compared across phases, and the idea that they have the same density or that density cannot be compared would miss how tightly packed the particles are in each phase.