# Which unit of pressure is used in the ideal gas law?

1. Sep 9, 2010

### escapistgoat

The ideal gas law states that pressure (P) is equal to the product of density (N), the ideal gas constant (R) and temperature (T):

P = N x R x T

I can't figure out which unit the pressure is actually in, although it does seems to work out as the figure I'm supposed to get with a 11706.85° increase in temperature is around 40x the pressure at 293.15° Kelvin:

N = 1.204 kg/cubic metre
R = 8.314472
T = 293.15
P = 2934.61

N = 1.204 kg/cubic metre
R = 8.314472
T = 12000
P = 120127.49

Thank you for considering this!

- Gordon

2. Sep 9, 2010

### stewartcs

The units must only be dimensionally correct. Absolute values are used for pressure and temperature.

CS

3. Sep 9, 2010

### Bob S

You need to start by writing the ideal gas law as P =RT/V, and substituting in the units for

R (joules/mol °K), T (°K), and V (m3).

[added] In this situation, V is actually in units of m3/mol

Bob S

Last edited: Sep 9, 2010