## Pressure Units

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

JacobHershenhouse3G
Posts: 32
Joined: Thu Jan 10, 2019 12:17 am

### Pressure Units

Hello, I'm just wondering if we should know all of the pressure unit conversions for the midterm/ if it will be given on the exam. Some of the homework problems include conversion steps so I'm not sure.

JiangJC Dis2K
Posts: 72
Joined: Fri Oct 12, 2018 12:16 am

### Re: Pressure Units

i feel like as a general, the only one important to know is torr since that appears most frequently and some constants on the equations sheet are given also in torr. 760 torr=1atm.

Sophia Ding 1B
Posts: 62
Joined: Fri Sep 28, 2018 12:16 am

### Re: Pressure Units

Are we always supposed to being the unit for atm in terms of calculations with pressure?

tierra parker 1J
Posts: 61
Joined: Fri Sep 28, 2018 12:17 am

### Re: Pressure Units

Sophia Ding 1B wrote:Are we always supposed to being the unit for atm in terms of calculations with pressure?

i think it depends on which constants you use like if you use R = 0.08206 L atm/K mol then you use atm but they also give you R = 62.364 L Torr/K mol on the equation sheet

Julia Lee
Posts: 80
Joined: Fri Sep 28, 2018 12:29 am

### Re: Pressure Units

Most of the time, they are provided on the constants and equations sheet. You can check the sheet on his website to see if it is on there. Usually the one on his website reflects what is given to us during the tests & midterms.

marisaimbroane1J
Posts: 69
Joined: Fri Sep 28, 2018 12:23 am

### Re: Pressure Units

There is a conversion to go from L*atm to Joules on the equation sheet, so when calculating work, you should try and get to atm in order to make the conversion to Joules. The constants/equations sheet is super helpful to look at before the test to know what you will be working with.

Calvin Patel 2H
Posts: 37
Joined: Fri Sep 28, 2018 12:22 am

### Re: Pressure Units

I think as long as you know the conversions between torr, bar, and atm, you'll be fine. Although I am not sure if he will give the values on the test or not.

Danny Elias Dis 1E
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: Pressure Units

While the conversion for units of pressure were not included on the last test, four different values for the gas constant (R) were provided: one includes joules, one includes atm, one includes bar, and one includes Torr. So, if your calculation involves the ideal gas law at all, chances are any pressure units will cancel out.