A 8.00-L container holds a mixture of two gases at 23 °C. The partial pressures of gas A and gas B, respectively, are 0.349 atm and 0.819 atm. If 0.210 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?

Answer 1

Calculate mols gas A from PV = nRT. You know its partial pressure, volume, R, T (remember T must be in kelvin).

Calculate mols gas B from PV = nRT in a similar manner.

Add mols gas A, mols gas B + 0.210 from the third gas. Use PV = nRT using total mols and solve for P which will be total P.

Post your work if you get stuck.