Question

The question is "the reaction CO + SO3 <=> CO2 + SO2 has two possible mechanisms. If the rate law for this reaction is rate=k[SO3] which mechanisms is correct? which step in THAT mechanisms is the slow step?
and the mechanisms are:
mechanism 1
CO + @ -> CO@
SO3 + CO@ -> CO2 + SO2@
SO2@ -> SO2 + @

Mechanism 2
SO3 -> SO2 + O
CO + O -> CO2

and for the answers I said the first one is the correct and the second one is the slow step. Is this right?

Answer 1

If the reaction below proceeds with a 96.8% yield, how many kilograms of CaSO4 are formed when 5.91 kg SO2 reacts with an excess of CaCO3 and O2?
2 CaCO3(s) + 2 SO2(g) + O2(g) → 2 CaSO4(g) + 2 CO2(g)