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

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.

To find the number of moles of solid CaCO3 required, you need to calculate the number of moles of CO2 produced according to the given information and then use the stoichiometry of the balanced equation.

Step 1: Calculate the number of moles of CO2

Given: Volume of gaseous CO2 at STP = 0.605 L

At standard temperature and pressure (STP),
1 mole of any ideal gas occupies a volume of 22.4 liters.

So, we can calculate the number of moles of CO2 (nCO2) as follows:
nCO2 = (Volume of CO2 at STP) / (Volume of 1 mole of CO2 at STP)
nCO2 = 0.605 L / 22.4 L/mol

Step 2: Use the stoichiometry of the balanced equation to find moles of CaCO3

From the balanced equation:
H2SO4(aq) + CaCO3(s) → CO2(g) + CaSO4(s) + H2O(l)

For every 1 mole of CaCO3, 1 mole of CO2 is produced.

Therefore, the number of moles of CaCO3 (nCaCO3) is equal to the number of moles of CO2 (nCO2).

nCaCO3 = nCO2

Now, substitute the value of nCO2 calculated in step 1:
nCaCO3 = 0.605 L / 22.4 L/mol

Finally, perform the calculation to determine the number of moles of solid CaCO3 required.