When a reaction mixture with a total volume of 1720 mL that contains 0.605 L of gaseous CO2 measured at STP dissolved in 940 mL of water was stoichiometrically produced as per the balanced equation, how many mol of solid CaCO3 were required?

H2SO4(aq) + CaCO3(s) → CO2(g) + CaSO4(s) + H2O(l)
.605L/22.4L=moles CO2
mol CaCO3=molCO2

3 answers

I'm not quite sure how to interpret the problem. If it is 0.605 L CO2 (and you are taking the entire amount of CO2) then your set up is correct. However, if you have CO2 dissolved in 940 mL and you are taking 605 mL of that solution, .....I don't know. Perhaps that scenario doesn't make sense.
how would you do it differently then
I don't know that I can offer another solution. It may be that all of those different mL and L are thre just to confuse you. And they succeeded for me. The method you have is ok, I think, if they interpret it the same way we did.