## Third Law concept and problem types

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

Milena Aragon 2B
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Third Law concept and problem types

I know what the third law is but i'm not sure what types of problems will we encounter where we need to apply the third law in order to solve the problem. Can anyone explain please?

Nathan Tran 4K
Posts: 92
Joined: Fri Sep 28, 2018 12:16 am

### Re: Third Law concept and problem types

We use the third law to identify changes in entropy in systems, surroundings, etc. Applications would be calculating delta s in terms of isothermal, isobaric, and isochoric conditions, calculating S in terms of Boltzmann's equation, and finding relationships in terms of delta s of the system, surroundings, and universe.

Jonathan Zhao 4H
Posts: 57
Joined: Fri Sep 28, 2018 12:26 am

### Re: Third Law concept and problem types

Yes, essentially the third law of thermodynamics is saying that at 0 degrees K, there is no vibrational, rotational, or translational entropy. The only possible entropy results from positional and residual. Thus, knowing the Boltzmann equation would come in handy when asked a question about the residual/positional entropy.

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