An insulated tank is divided by a thin partition.

(a) On the left is 0.79 mole of N2 at 1 bar and 298 K; on the right is 0.21 mole of O2 at 1 bar and 298 K. The partition ruptures. What is DSuniv for the process?

(b) On the left is 0.79 mole of N2 at 2 bar and 298 K; on the right is 0.21 mole of O2 at 1 bar and 298 K. The partition ruptures. What is DSuniv for the process?

[Hint Consider the entropy change of each gas separately and add them together. To do this, you will need to use the concept of partial pressure.]