What effect does temperature typically have on gas density?

• A. Gas density increases with temperature
• B. Gas density decreases with temperature
• C. Gas density remains unaffected by temperature
• D. Gas density multiplies with temperature

Answer: (B)

Gas density is inversely related to temperature, which means that as temperature increases, gas density decreases. This relationship is primarily explained by the ideal gas law, which states that for a given amount of gas at a constant pressure, an increase in temperature results in an increase in the volume of the gas. Since density is defined as mass divided by volume, if the volume increases while the mass remains constant, the density must decrease.

In practical terms, when you heat a gas, the molecules move faster and tend to spread apart, leading to a lower density. Conversely, cooling a gas will decrease the volume and increase its density, assuming the pressure remains constant. This is a crucial concept in various applications, including diving, where changes in gas density due to temperature can affect buoyancy and the behavior of gas mixtures under different conditions.