## Bar vs. atm

klarratt2
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Bar vs. atm

When do we use bar and when do we use atm? Does it matter? What is the difference?

EllerySchlingmann1E
Posts: 76
Joined: Fri Sep 28, 2018 12:24 am

### Re: Bar vs. atm

It just depends on how the partial pressure of the gas is given. If it is given in bar, use that and same for atm. Just make sure to use the correct form of R if you are converting to a concentration using PV=nRT. The difference between the two is numeric but they serve similar purposes for us.

Cynthia Ulloa
Posts: 52
Joined: Fri Feb 23, 2018 3:02 am

### Re: Bar vs. atm

They are both a measure of pressure so you can use either one depending on what the question gives you. If they give you pressure in terms of atm then you would use atm or vice versa.

Saman Andalib 1H
Posts: 73
Joined: Fri Sep 28, 2018 12:16 am

### Re: Bar vs. atm

They are both measurements of pressure in a system for the equilibrium expression. There is no difference in their usages in the context of a problem, but if you are converting from a concentration to a partial pressure (or vice versa), make sure that the constant R is in the correct units of either atm or bars.