Chemistry
posted by Daniel .
When 0.100 mol of CaCO3 (s) and 0.100 mol of CaO (s) are placed in an evacuated container with a volume of 10.0L and heated to 385 K, PCO2 = 0.220 atm after equilibrium is established: CaCO3(s) ⇌ CaO (s) + CO 2 (g) An additional 0.300 atm of CO2 (g) is pumped in. What is the total mass (in grams) of CaCO3 after equilibrium is reestablished?

This problem seems too simple. If I've screwed up I'm sure another tutor will let me know.
CaCO3(s) ==> CaO(s) + CO2(g)
Kp = pCO2 = 0.22 atm.
So if we add 0.3 atm EXTRA, the reaction must shift to use up the extra 0.3.
Use PV = nRT and solve for n = number of moles CO2 and that will be the as moles CaCO3. Then add the extra moles toltghe 0.100 mol to start to find total CaCO3 after equilibrium is reestablished.