Bar vs. atm

[klarratt2]

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

[EllerySchlingmann1E]

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]

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]

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.

[Lia Inadomi 1I]

1 bar = 0.987 atm, but both are just units of pressure. Hope this helps!