7th edition 4I. 9

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

Alyssa Bryan 3F
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7th edition 4I. 9

Initially an ideal gas at 323 K occupies 1.67 L at 4.95 atm. The gas is allowed to expand to 7.33 L by two pathways: (a) isothermal, reversible expansion; (b) isothermal, irreversible free expansion. Calculate delta S total, delta S, and delta S surroundings for each pathway.
How would you solve for these?

Sam Joslyn 1G
Posts: 34
Joined: Fri Sep 28, 2018 12:20 am

Re: 7th edition 4I. 9

Since entropy is a state function, I believe it doesn't matter how exactly it increases (irreversible or reversible) so the change of enthalpy for the system is going to be the same for both expansions. The difference comes from the change in entropy of the surroundings. For a reversible process, the total change in entropy is 0, so the change in entropy for the surroundings would be equal to negative change of entropy for system. For the irreversible process, the change of entropy of the surroundings is 0, so it follows that the total change in entropy is equal to the change of entropy of the system

Karina Jiayu Xu 4E
Posts: 58
Joined: Fri Sep 28, 2018 12:29 am

Re: 7th edition 4I. 9

Calculate using two separate formulas given in lecture then compare the entropy changes