softmatter:Ideal Gas

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An ideal gas is a hypothetical gas consisting of particles of zero volume that experience no intermolecular forces, but undergo elastic collisions with the walls.

Ideal Gas Law

Thermodynamic treatment

Formulated by Clapeyron, the ideal gas law can be expressed as:

PV = nRT

where, P is pressure, V is volume, n is the amount of material (mol or lb-mol), R is the gas constant and T is the temperature. For various units, R has the value of:

Gas constant R (Units)
8.314472 meter3·Pascal·Kelvin-1·mol-1
0.08205784 Liter·atm·Kelvin-1·mol-1
62.3637 Liters·mmHg·Kelvin-1·mol-1
10.7316 ft3·psi·°Rankin-1·lb-mol-1

Statistical Mechanics treatment

Additionally, the gas law can be expressed in terms of the number of atoms/molecules:

PV = NkT

where P, V, and T are unchanged, but now N corresponds to the number of atoms/molcules, and k is the Boltzmann constant. The Boltzmann constant has the following values for various units:

Boltzmann constant k (Units)
1.380 6504x10-23 Joules/Kelvin
8.617 343x10-5 electron-volt/Kelvin
1.3807x10-16 erg/Kelvin
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