posted by Jenny .
We have a tank that contains O2 at 146 mmHg, N2 at 146 mmHg, and CO2 at 138 mmHg. We then add 135 mmHg of Ar. What is the pressure in the tank?
A funny way of putting the problem; if you are saying you add enough Ar to make pressure Ar = 135 mm Hg, the total P in the tank is the sum of the partial pressures of each gas.