## When to use internal energy equation

$\Delta U=q+w$

Shanzey
Posts: 120
Joined: Wed Sep 18, 2019 12:20 am

### When to use internal energy equation

On the constants and equations sheet, there is an equation for calculating just internal energy: U=(3/2)nRT. When do we need to use this equation? Were there any questions using this in the homework?

Posts: 103
Joined: Sat Aug 24, 2019 12:15 am

### Re: When to use internal energy equation

I believe we use this equation when we are finding molar kinetic energy. I do also remember a homework question, I believe 4.c.3 or something, where we needed this to find the change in energy with constant pressure.

Dina Marchenko 2J
Posts: 54
Joined: Thu Jul 25, 2019 12:16 am

### Re: When to use internal energy equation

This equation is related to the internal energy of an ideal gas and the heat capacities at constant pressure and volume for various gas molecules. I don't think we necessarily need to use it for this class.

Rebekah Alfred 1J
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Joined: Thu Jul 11, 2019 12:15 am
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### Re: When to use internal energy equation

In lecture, Dr. Lavelle mentioned this equation while explaining how a system loses energy as a result of doing work of expansion.