## Irreversible and Reversible Processes

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

JChen_2I
Posts: 107
Joined: Fri Aug 09, 2019 12:17 am

### Irreversible and Reversible Processes

Can someone explain how irreversible and reversible processes affect entropy of the surroundings and universe?
For example in 4I9, why does an isothermal, reversible expansion mean there's no change in total entropy? And why does an isothermal, irreversible free expansion mean there's no change in entropy of the surroundings?
Thanks!

Andrew F 2L
Posts: 103
Joined: Sat Aug 17, 2019 12:17 am

### Re: Irreversible and Reversible Processes

I know that, according to the 2nd law of thermodynamics, in a reversible reaction, the entropy of the universe is constant and for a irreversible process, the transfer of heat from a hot to a cold object causes entropy to increase in the universe because it is the transfer of energy occuring

andrewcj 2C
Posts: 102
Joined: Thu Jul 11, 2019 12:17 am

### Re: Irreversible and Reversible Processes

In an irreversible process, heat is transferred out of the system, which increases the entropy of the universe. However, in reversible processes, theoretically, no heat is lost, which means the entropy of the universe does not change.