Question

Two gases with different masses are injected into the opposite ends of a long tube at the same time and allowed to diffuse toward the center. what is the most likely observation?
a) it will take approximately 3 minutes for the gases to mix.
b) the gases will mix closer to the end that holds the heavier gas.
c) the gases will mix closer to the end that holds the lighter gas.
d) the gases will mix closer to the middle of the long tube.

Answer 1

Answer:

b) the gases will mix closer to the end that holds the heavier gas.

Explanation:

The question is based on the Graham's law of diffusion.

• According to Graham's law of effusion, the rate of effusion of gases is dependent on the density of the gases. Such that the rate of effusion a gas is inversely proportional to the square root of its density.
• Therefore, a lighter gas effuses faster compared to a heavier gas.
• In this case, the gases will mix closer to the end that holds the heavier gas, because the lighter gas will effuse faster and cover a longer distance compared to the heavier gas.
• For instance , if we take two gases ammonia (NH4) and Chlorine (Cl2), if they were allowed to effuse from opposite ends of a long tube, then NH4 would effuse faster since it is lighter than chlorine. Consequently, the two would mix near the end that holds chlorine gas.