What diffuses faster: a gas sample into a vacuum container, or a gas sample into an air filled container?

A gas sample into a vacuum diffuses faster than a gas sample into an air-filled container.

Explanation:

Diffusion

When a gas is introduced into a closed space, the molecules of the gas move freely and spread throughout the closed space.

The gas molecules tend to move from higher concentration to lower concentration area so that the concentration of gas throughout the closed space comes in equilibrium. This happens because higher concentration spaces have a greater number of gas molecules and vice-versa. In other words, gas molecules move towards the spaces having less concentration, i.e., they have a smaller number of gas molecules, and hence, can accommodate additional gas molecules.

This process of dispersion of gas molecules, as a result of difference in concentration, is called diffusion. The speed of diffusion is affected by the collisions suffered by the gas molecules.

When the molecules of gas disperse in any space, they have a tendency to travel in a straight line. In this process, they hit the molecules of other gases in the same space which causes a decrease in the speed of the molecules of gas hence, slowing the process of dispersion or diffusion.

Diffusion in air-filled container

When a gas is introduced into a closed container which is already filled with air, the molecules of the newly-introduced gas, as per their tendency, tend to move throughout the closed container irrespective of the concentration gradient.

Diffusion in a vacuum container

Whereas, in vacuum, the molecules of the introduced gas do not face any collisions with any molecules of other gas. The molecules of gas move freely until they collide with the sides of the container. The only collision occurring in a vacuum container is when the molecules hit the containers. Hence, gas diffusion takes place faster in a closed container having vacuum than a closed container which is already filled with air.