## Laws of thermodynamics

$\Delta U=q+w$

Jessica Castellanos
Posts: 102
Joined: Sat Aug 24, 2019 12:17 am
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### Laws of thermodynamics

What are the three laws of thermodynamics? I was a bit confused when they were mentioned in class.

Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

### Re: Laws of thermodynamics

1. delta U = heat+work
2. For reversible system, deltaS of universe equals 0.
3. at 0K for a perfectly ordered molecule, the entropy change is 0

Eesha Sohail 1D
Posts: 100
Joined: Sat Aug 17, 2019 12:16 am

### Re: Laws of thermodynamics

The corollary to law #2 is that since no real process is perfectly reversible, change in entropy of the universe is always positive, correct? But why can no real process be completely reversible?