Don't gases have a molar density of 1mol/ 22.4L at STP? Can't thatbe converted to grams per liter.

Here is the long way: \(\displaystyle{C}{a}{C}{O}_{{{3}}}+{2}{H}{C}{I}+{C}{a}{C}{I}{2}+{C}{O}_{{{2}}}+{H}{20}\)

Thus 1004 grams of calcium carbonate only 95% pure:

grams of \(CaCO_3: 0.95(1004.0g)\)

Can convert that to grams of carbon dioxide:

\(0.95(1004.0g CaCO_3) * (1mol CaCO_3/100g CaCO_3) * (1 mol CO_2/1molCaCO_3) * (44 g CO_2/ 1 mol CO_2) = 419.7\) grams

That is 419.7 grams in 225 L, so density = 419.7g/225L = 1.87g/L