In this Demonstration, you can solve for any of the four variables in the ideal gas law,
, given the other three. In SI units the pressure
is expressed in pascals (Pa), equal to
. Since one standard atmosphere equals 101.325 kPa, the SI pressure units are given in kPa. Volume
in K, and number of moles
in mol. The universal gas constant
J/K mol (it is divided by 1000 so
comes out in kPa).
In the older, but still extensively used liter-atmosphere system of units,
is given in atm and
in L, and the gas constant is
L atm/K mol. The temperature on the Celsius scale (°C) is also shown.
At low temperatures or high pressures, the ideal gas law becomes inaccurate and you must use another equation of state, such as the van der Waals equation.