Conversion of gas simulation results to physical units

compute the velocity of He at 0 °C

equipartition

m vx^2==kB T

Needs["PhysicalConstants`"]

Needs["Units`"]

BoltzmannConstant

T0K=ConvertTemperature[0,Celsius,Kelvin]

http : // en.wikipedia.org/wiki/Atomic_mass _unit

Convert[AtomicMassUnit,Kilogram]

compute the mass of He (kg)

ElementData["Helium","AtomicWeight"]

mHe=Convert[ElementData["Helium","AtomicWeight"] AtomicMassUnit,Kilogram]

vxHe0K=Sqrt[(BoltzmannConstant T0K Kelvin)/mHe]

vxHe0Km=Convert[vxHe0K,Meter/Second]

Convert[vxHe0K,(( Kilo Meter)/Hour)]

SpeedOfSound

vxHe0Km/SpeedOfSound

http : // en.wikipedia.org/wiki/Molar_volume
The molar volume of an ideal gas at 1 atmosphere of pressure and at 0 °C is

MolarVolume

AvogadroConstant

compute the volume of 1000 particles of an ideal gas at 1 atmosphere of pressure and at 0 °C

V1000=1000 MolarVolume/AvogadroConstant