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

AI Thread Summary
The ideal gas law expresses pressure (P) as the product of density (N), the ideal gas constant (R), and temperature (T). The discussion highlights confusion regarding the units of pressure derived from the equation. It is clarified that the ideal gas law can be rewritten as P = RT/V, where R is in joules per mole per Kelvin, T is in Kelvin, and volume (V) is in cubic meters per mole. The importance of using absolute values for pressure and temperature is emphasized. Understanding these units is crucial for accurate calculations in gas law applications.
escapistgoat
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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
 
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escapistgoat said:
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

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

CS
 
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
 
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