Conversion of gas simulation results to physical units

Remove["Global`*"]

compute the velocity of He at 0 °C

equipartition

m vx^2==kB T

Needs["Units`"]

kB=UnitConvert[Quantity["BoltzmannConstant"]]

T0K=UnitConvert[Quantity[0, "DegreesCelsius"],"Kelvins"]

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

mHe=UnitConvert[ElementData["Helium","AtomicWeight"]]

vxHe0K=Sqrt[(kB T0K)/mHe]

UnitConvert[vxHe0K, "km/h"]

SoS=UnitConvert[Quantity["SpeedOfSound"]]

vxHe0Km/SoS

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

UnitConvert[Quantity["MolarVolume"]]

UnitConvert[Quantity["AvogadroConstant"]]

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

V1000=1000 UnitConvert[Quantity["MolarVolume"]/Quantity["AvogadroConstant"]]