Using the equation CaCo3(s) -> CaO(s) + CO2(g), if 25.0 ml of carbon dioxide is produced at 0.85 atm and 22 degrees Celsius, what mass of calcium carbonate is decomposed?
CaCo3(s) -> CaO(s) + CO2(g)
Use PV = nRT, plug in the conditions listed and solve for n = number mols CO2 at those conditions. The you know from the equation that 1 mol CO2 comes from 1 mol CaCO3. The grams CaCO3 = mols CaCO3 x molar mass CaCO3.
Remember to use C in kelvin.