## 8.31

Rachel Brown 3A
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

### 8.31

On 8.31, the solution states that the molar heat capacity of a monatomic ideal gas at constant pressure is = 5/2 R and later states that the molar heat capacity of a monatomic ideal gas at constant volume is = 3/2 R. What does this mean and how can you find it?

Posts: 62
Joined: Thu Jul 27, 2017 3:01 am

### Re: 8.31

The general equation that you're going to use is nC(delta)T or mC(delta)T. Now, C can either be Cp, which is constant pressure or Cv, which is constant volume. When you have Cp, you would use 5/2 R. When you have Cv, you would use 3/2 R. The R will be the gas constant, so you have to look at the units to find out which gas constant to use.

Ya Gao
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

### Re: 8.31

It means that when a gas is working as an ideal gas, its Cv and Cp will be 3/2R and 5/2R. It can be found on the equation sheet.

Kevin Ru 1D
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

### Re: 8.31

Just to add on that R represents the gas constant which varies depending on what units you are using. As mentioned above, it can be found on the constant and equations sheet on Dr. Lavelle's website.

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