Question

If 91.5 mol of an ideal gas occupies 69.5 L at 31.00°C, what is the pressure of the gas?

Answer 1

You will need to use the Ideal Gas Law to solve this problem:

`PV = nRT`

Explanation:

To find pressure `(P)`, derive from the Ideal Gas Law:

`P = (nRT)/V`

Gather up your known values, and plug them into the equation.

There are a few points to make here, Temperature `(T)` must be converted to Kelvin.

`R` = Ideal Gas Constant. This can have many forms. The one I used below is the one that I am most familiar with. Be aware of this though, and check which value you should be using per your curriculum.

`n = 91.5 mol`
`V = 69.5L`
`T = 31.0°C + (273.15K) = 304.15K`
`R = 8.314J/(mol*K)`

Finally,

`P = ((91.5mol)(8.314J/(mol*K))(304.15K))/(69.5L)`

`P = (x)atm`