Question

What is the pressure of a gas in `"atm"` if its pressure is `"85 kPa"`?

Answer 1

I can easily remember that `10^5` Pa is in `1` bar, and I also remember that `1` bar is equal to slightly less than `1` atm, so overall I just remember this:

`1` bar `= 1` atm `* (100000/101325)`

and since there are `10^5` Pa in `1` bar, this becomes:

`cancel(100000 Pa) = "1 atm" * ((cancel(100000 Pa))/(101325 Pa))`

`1 = "1 atm"/"101325 Pa" =>` `"101325 Pa" = "1 atm"`

Since there are `101325` Pa in `1` atm, there are `101.325` kPa in `1` atm.

Answer 2

`101325 "Pa"=1 "atm"`

`101325 cancel"Pa"` x `(1 "kPa")/(1000 cancel"Pa")=101.325 "kPa"`

Therefore, `101.325 "kPa"=1 "atm"` .

So if you have a gas at a pressure of `85 "kPa"` and want to convert the pressure to atm, you would do the following:

`85cancel"kPa"` x `(1"atm")/(101.325cancel"kPa")=0.84"atm"`