CHEMISTRY COMMUNITY

Questions M3 reads: When limestone, which is principally CaCO3, is heated, carbon dioxide and quicklime, CaO, are produced by the reaction CaCO3 (s) -> CaO (s) + CO2 (g). If 17.5 g of CO2 is produced from the thermal decomposition of 42.73 g of CaCO3, what is the percentage yield of the reaction?


Since it gives you that 42.73 g of CaCO3 was used, can you assume that one is the limiting reactant? Or should you test it first? If you should test if the other is the limiting reactant, how do you test it?

Thanks!

Never mind regarding this question. There was only one reactant.

But in other cases, would they give you the masses of both/all the reactants to determine which one is limiting? Thank you!

If only one reactant mass is given, you can assume that that is the limiting reactant. Otherwise, you will need to test to see which reactant is limiting :)

Normally, yes. Both masses should be given to then determine which reactant is limiting and which is in excess. If only one is given, I would assume that that reactant is the limiting reactant since no other information is given. However, based on the context of the question, you may want to always double check.