The relative formula mass of CaO is 56 and the relative formula mass of CO2 is 44. What is the mass of CaO that can be obtained from 200 g of CaCO3. CaO3 -> CaO + CO2

We are given the relative formula mass (RFM) of CaO and CO₂, we should therefore calculate the RFM of CaO^₃:

RFM of CaCO₃ = 40 + 12 + (16 x 3) = 100

If we look at the reaction in the question, we can see one CaCO₃ goes to one CaO and one CO₂.

Effectively, in 200 g we have 2 lots of CaCO₃, therefore we can make 2 lots of CaO and two lots of CO₂.

Therefore we can make 2 x 56 g = 112 g of CaO from 200g of CaCO₃.