Stupid question but when we are heating up CaCO3, we get CaO and CO2 right? But what happens when it doesn't fully decomp completely? I'm figuring the ratio of CaO and CO2 is 1:1, but how would the mole ratio change if it doesn't fully decomp? Also.. if the CaCO3 was contaminated by a thermally stable compound, how would this affect the decomp and ratio? Thanks for the help!

the mole ratio would not change, you would just have a mixture at the end of CaO and CaCO3 with some carbon dioxide given off.

 

assume the thermally stable compound does not chemically react with either CaCO3, CO2 or CaO then it will not affect the decomposition.

the only other possible compound that could be made if the carbonate was damp would be calcium bicarbonate, but that would only last a second or 2 at the very most.