## R constant in PV=nRT

DesireBrown1J
Posts: 98
Joined: Wed Sep 18, 2019 12:18 am

### R constant in PV=nRT

What exactly is the ideal gas constant in R? When I looked it up, I realized that there are two different ones to use. How do we determine which one to use based on what information is given to us in a problem?

AlyshaP_2B
Posts: 112
Joined: Wed Sep 18, 2019 12:19 am

### Re: R constant in PV=nRT

I think the gas constant will be given to us either in the question or on an equation sheet!

nehashetty_2G
Posts: 102
Joined: Thu Jul 25, 2019 12:15 am

### Re: R constant in PV=nRT

I think it will most likely by R=8.314 J/(Kmol) because that is what Lavelle gave on the formula/constant sheets in 14A. In general just look at the units to figure out what to use, or to see if you need to manipulate the constant.

Areli C 1L
Posts: 95
Joined: Wed Nov 14, 2018 12:19 am

### Re: R constant in PV=nRT

Most likely it will be R=8.314 J/(K*mol) as it will be cancelled out with T= Kelvin. Also it probably will be given in our constant sheet on exam days.

Natalie Benitez 1E
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### Re: R constant in PV=nRT

I believe the constant will be given to us in the constant sheet so what don't really need to worry about it.

Pablo 1K
Posts: 118
Joined: Sat Feb 02, 2019 12:15 am

### Re: R constant in PV=nRT

You would check your units to see which one you would utilize!

Abigail_Hagen2G
Posts: 107
Joined: Fri Aug 09, 2019 12:17 am

### Re: R constant in PV=nRT

For homework though the one on the equation sheet should work

nicole-2B
Posts: 103
Joined: Fri Aug 30, 2019 12:18 am

### Re: R constant in PV=nRT

Gas constant, R = 8.314 J·K-1·mol-1 = 8.206 x 10-2 L·atm·K-1·mol-1 = 8.314 x 10-2 L·bar·K-1·mol-1= 62.364 L·Torr·K-1·mol-1
This is what was on the constants and formualas sheet on Dr. Lavelle's website.

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

### Re: R constant in PV=nRT

DesireBrown1J wrote:What exactly is the ideal gas constant in R? When I looked it up, I realized that there are two different ones to use. How do we determine which one to use based on what information is given to us in a problem?

the way to determine which constant to use would be to look at the units and find which one matches! for example, if pressure is in pascals you would use the constant associated with that, or if it were in atm then you would use that one.

Uisa_Manumaleuna_3E
Posts: 60
Joined: Wed Sep 21, 2016 2:56 pm

### Re: R constant in PV=nRT

You don't have to worry too much though about which one of the R constant values to use, because (like everyone else said) the units will match up to the one we're supposed to use. So if you end up plugging in one of the other R values to the equation, not all of the units will cancel out and your answer will have some strange blend of every unit on the sheet. At least for me, that makes it pretty obvious that I chose the wrong one and have to go back a little.