college chemistry
posted by Liz on .
Calcium oxide (CaO), an important ingredient in cement, is produced by decomposing calcium carbonate (CaCO3) at high temperature:
CaCO3(s) → CaO(s) + CO2(g)
In one particular reaction, 40 g of CaCO3 is heated at 750°C in a 5.0 L vessel. The pressure of CO2 is 0.12 atm after 4.0 minutes. What is the average rate of CO2 production in moles per minute during the 4 minutes?
If you assume this rate of decomposition remains constant, how many minutes will it take for the entire sample of CaCO3 to decompose?
Help?

PV = nRT. Solve for n which will give you moles/4.0 minutes. You need moles/1 minute.