Graham's Law describes the rate of what process relative to molar mass?

Graham's Law describes the rate of what process relative to molar mass?

• A. The rate of diffusion is directly proportional to the square root of temperature
• B. The rate of effusion is inversely proportional to the square root of molar mass
• C. Gases diffuse from low concentration to high concentration
• D. Diffusion occurs only in liquids

Answer: (B)

Graham's Law is about how fast a gas escapes through a small opening (effusion), and it shows that the rate is inversely proportional to the square root of the gas’s molar mass. In other words, lighter gases move and leak out faster when temperature and pressure are the same. The key relationship is rate ∝ 1/√M, so comparing two gases, the lighter one has a higher rate by the factor √(M heavier / M lighter). For example, hydrogen (very light) will effuse much faster than xenon (very heavy) under identical conditions. This law specifically ties the rate to molar mass, not to temperature alone, which is why the statement about effusion being inversely proportional to the square root of molar mass is the best description. Also, diffusion does occur in gases (not just liquids), and diffusion proceeds from regions of high concentration to low concentration, not the reverse, which is why those alternatives don’t fit Graham’s Law.

Graham's Law is about how fast a gas escapes through a small opening (effusion), and it shows that the rate is inversely proportional to the square root of the gas’s molar mass. In other words, lighter gases move and leak out faster when temperature and pressure are the same. The key relationship is rate ∝ 1/√M, so comparing two gases, the lighter one has a higher rate by the factor √(M heavier / M lighter). For example, hydrogen (very light) will effuse much faster than xenon (very heavy) under identical conditions.

This law specifically ties the rate to molar mass, not to temperature alone, which is why the statement about effusion being inversely proportional to the square root of molar mass is the best description. Also, diffusion does occur in gases (not just liquids), and diffusion proceeds from regions of high concentration to low concentration, not the reverse, which is why those alternatives don’t fit Graham’s Law.