How does the density of chlorine gas compare to that of air?

Chlorine gas is indeed more dense than air. The average molecular weight of air is approximately 29 g/mol, while the molecular weight of chlorine gas (Cl₂) is about 70.9 g/mol. This higher molecular weight means that chlorine gas will be heavier than the average mixture of the gases that make up air, causing it to settle in lower areas and accumulate.

Understanding the behavior of gases based on their density is crucial in various applications, particularly in safety and environmental contexts. When handling chlorine gas, knowing its density compared to air informs procedures regarding its storage, transport, and incident response, as heavier-than-air gases can pose inhalation hazards if they concentrate in low-lying areas.