Mass and penetration are __________.

Mass and penetration are __________.

• A. Inverse
• B. Direct
• C. Equal
• D. Unrelated

Answer: (A)

Mass and penetration are inversely related in the context of gas diffusion through a barrier. At the same temperature, lighter molecules move faster on average than heavier ones because their rms speed scales with the inverse square root of their molar mass (v_rms ∝ √(1/M)). Diffusion or penetration through a membrane depends on how quickly molecules reach and interact with the barrier, so faster-moving, lighter molecules penetrate more quickly while heavier molecules penetrate more slowly. This is captured quantitatively by Graham’s law, which states that the rate of diffusion or effusion is proportional to 1/√M. So as mass increases, the rate of penetration decreases, giving an inverse relationship.

Mass and penetration are inversely related in the context of gas diffusion through a barrier. At the same temperature, lighter molecules move faster on average than heavier ones because their rms speed scales with the inverse square root of their molar mass (v_rms ∝ √(1/M)). Diffusion or penetration through a membrane depends on how quickly molecules reach and interact with the barrier, so faster-moving, lighter molecules penetrate more quickly while heavier molecules penetrate more slowly. This is captured quantitatively by Graham’s law, which states that the rate of diffusion or effusion is proportional to 1/√M. So as mass increases, the rate of penetration decreases, giving an inverse relationship.