Limestone stalactites and stalagmites are formed in caves by the following reaction: Ca2+(aq) + 2HCO3- ➡ CaCO3(s) + CO2 (g) + H2O (g)

Question

If 3.45 moles of calcium carbonate form at 298K under one atmosphere pressure, What is the total volume of gaseous product produced?

Answer 1

Since 3.45 mols of CaCO3 form, and there is a 1:1 molar relationship between CaCO3 and CO2, and CaCO3 and H2O, then there also must be 3.45 mols of CO2 formed and 3.45 mols of H2O formed.

The total number of mols of gas in the container is thus:

3.45 mols CO2 + 3.45 mols H2O = 6.90 mols gas total

Using the ideal gas law, we can find the total volume of the container:

PV=nRT —> V = nRT/P

V = (6.90 mols)(0.08206 L-atm/mol-K)(298 K) / (1 atm)

V = 168 L