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

In summary, the ideal gas law states that pressure (P) is equal to the product of density (N), the ideal gas constant (R), and temperature (T). The units for pressure and temperature must be dimensionally correct. Absolute values are used for pressure and temperature. When using the equation P = RT/V, the units for R are joules/mol °K, T is in °K, and V is in m3/mol.
  • #1
escapistgoat
3
0
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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  • #2
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
 
  • #3
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:

1. What is the ideal gas law?

The ideal gas law is a mathematical equation that describes the relationship between the pressure, volume, temperature, and number of moles of an ideal gas. It is written as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature.

2. Which units of pressure are used in the ideal gas law?

The ideal gas law can be used with various units of pressure, including atmospheres (atm), pascals (Pa), millimeters of mercury (mmHg), and torr. However, the most commonly used unit of pressure in the ideal gas law is atmospheres.

3. Why is the ideal gas law important?

The ideal gas law is important because it allows us to make predictions about the behavior of gases under different conditions. It is used in various fields of science, such as chemistry, physics, and engineering, to calculate the properties of gases.

4. How do you convert between different units of pressure in the ideal gas law?

To convert between different units of pressure in the ideal gas law, you can use conversion factors. For example, to convert from atmospheres to pascals, you can multiply the value in atmospheres by 101,325 (the number of pascals in 1 atmosphere). It is important to pay attention to the units when using the ideal gas law to ensure accurate calculations.

5. Can the ideal gas law be used for all gases?

The ideal gas law is based on certain assumptions, such as that the gas particles have no volume and do not interact with each other. Therefore, it is most accurate for ideal gases. However, it can also be used for real gases under certain conditions, such as low pressures and high temperatures.

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