Entropy of a contained ideal gas mixture

[Airsteve0]

If an ideal gas mixture is heated inside of a container which does not expand then does the entropy increase? Outside the container I know it would but inside the container the gases can't really become more disordered.

 

[Mapes]

But particle speeds are higher, so there are more possible speeds that any particular particle can assume. Heating thus provides more possible microstates.

Heating a system always increases its entropy.

 

[Airsteve0]

thank you for the clarification!