Chemistry
posted by Brandon .
A 3.43 L flask is filled with carbon monoxide at 27 °C until the pressure is 8.31 atm. Calculate the total pressure after 2.09 moles of carbon dioxide has been added to the flask. (R=0.082 Latm/K mol)

Use PV = nRT and solve for n = number of mols CO.
Add n CO and n CO2 for total mols, substitute into PV = nRT and solve for P.
There is another way which is a little faster. Use PV = nRT and solve for P CO2, then add p CO2 to p CO for total P.