Diffusion and Effusion Rates

If an unknown gas diffuses twice the speed of O₂ (M=32) , what would its molar mass be

• 2
• 4
• 6
• 8

how many times faster does He effuse compared to N₂ (He = 4  N₂ = 28)

• 1.2 times faster
• 2.65 times faster
• 7 times faster
• 0.377 times faster

why would O₂ effuse faster than CO₂ in the same room

• because it has more energy
• because it has a greater molar mass
• because oxygen has a higher temperature
• they will effuse the same because the temperature is fixed

what is the rate of effusion for NH₃ (M=17) if the rate of effusion for SO₂ (M=17) is 0.800m/s

• 1.55 m/s
• 2.00 m/s
• 0.500m/s
• 0.800m/s

Grahams law of effusion states that The rate of effusion of gases at the same temperature and pressure are;

• directly proportional to the mass
• inversely proportional to the molar mass
• inversely proportional to the square root of the molar mass 
• directly proportional to the square root of the molar mass 

diffusion and effusion are the same in which way?

• both describe particles moving
• both describe the movement through a tiny whole

The rate of effusion is _______________ proportional to the square root of its' molar mass. 

• Directly
• Inversely 

Lighter gases have a ________________ rate of effusion.

• faster 
• slower
• rate of effusion does not depend on mass.

Effusion is

• used to describe the combustibility of a gas.
• ability of a gas to escape through a tiny opening
• what occurs after diffusion.
• the ability of a gas to mix with other gases.

An unknown gas diffuses 0.25 times as fast as helium gas (He). What is the molecular mass of the unknown gas? 

• 64 g/mol
• 16 g/mol
• 32 g/mol
• 4 g/mol