# Volume of a Gas from a thermal decomposition

• Chemistry
Homework Statement:
Thermal decomposition of calcium hydrogen carbonate yields calcium carbonate water and carbon dioxide. Calculate the volume of carbon dioxide measured at 0 °C and 1.00 atm that is obtained by heating 80.0 grams of calcium carbonate
Relevant Equations:
gas laws
Ca(HCO3)2 -> CaCO3 + H2O + CO2

First I evaluate the moles of calcium carbonate (don't mind the units, just to save time)

##\frac {80.0}{40,00+12.01+3*16,00}= 0,799 mol##

From the equation, correct me if I am wrong , one mole of CaCO3 is proportional to one mole of CO2, so from this I can say that also CO2 has 0,799 mol.

Using the ideal gas law equation PV=nRT, I can compute V:

##V=\frac{nRT}{P} ##

inserting the values, I don't get the expected result, so I suspect that something is wrong, Any help ?