When Two Gases Are Mixed the Entropy?

Entropy increases when two substances mix with each other. For example, the entropy of mixing of two different gases are given by ΔS=2NklnVfVi. But, the entropy doesn't increase when the two gases mixing are same.

Why Does entropy increase on mixing of two gases?

1 Entropy Change in Mixing of Two Ideal Gases

Equation (7.1) states that there is an entropy increase due to the increased volume that each gas is able to access. ... As we watched, as the gases mixed, there would be more and more of the different color molecules in the regions that were initially all white and all red.

What happens when two gases are mixed?

One of the properties of gases is that they mix with each other. When they do so, they become a solution—a homogeneous mixture. ... Each component of the mixture shares the same temperature and volume. (Remember that gases expand to fill the volume of their container; gases in a mixture do that as well.)