If the reaction below proceeds with a 96.8% yield, how many kilograms of CaSO4 are formed when 5.27 kg SO2 reacts with an excess of CaCO3 and O2?

Question

2 CaCO3(s) + 2 SO2(g) + O2(g) 2 CaSO4(g) + 2 CO2(g)

Answer 1

Here is a worked example of a similar problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html
Post your work if you get stuck.

Answer 2

why is the enthalpy chance for a reaction proportional to the quantity of reactants