The Equation of State for an Ideal Gas

So we are assuming that the product p V is proportional to T for a fixed mass of gas.

For 1 mole of an ideal gas we call the constant of proportionality R, the ideal gas constant.

So we get      p V = R T

for n moles the equation becomes     p V = n R T

This is the equation of state for an ideal gas. Knowing any two of p, V or T for fixed amount of gas we can calculate the third quantity.

Experiment gives a value for r of about 8.3 J/mol K

If p V = a constant x T then p V / T for a certain amount of gas is constant. This gives us another useful equation.