# How does the ideal gas law differ from the combined gas law?

##### 1 Answer

May 17, 2014

The **combined gas law** relates the variables pressure, temperature, and volume whereas the ideal gas law relates these three including the number of moles.

The equation for the **ideal gas law** is PV/T = k

P represents pressure, V represents volume, T temperature in kelvin

k is a constant.

The ideal gas PV= nRT

Where P,V,T represent the same variables as in the combined gas law. The new variable, represents the number of moles.

R is the universal gas constant which is

0.0821 (Liters x atmospheres/mol x Kelvin).

You can rewrite equation as PV/nT =R