Marble (calcium carbonate) reacts with hydrochloric acid solution to form calcium chloride solution, water, and carbon dioxide. What is the percent yield of carbon dioxide if 3.65 g of the gas is collected when 10.0 g of marble reacts?

CaCO3+2HCl→CaCl2+H2O+CO2

You have to find which is limiting first, we take 10g of marbles10g marbles*1 mol marbles/40+12+3 (16) g marbles*1 mol CO2/1 mol marbles=0.4 mol CO2

Then0.4 mol CO2 * 12+2 (16) g CO2/1 mol CO2=17.6g of CO2

Based on theoretical calculations, you should get 17.6g of CO2, but it turns out that you only have 3.65g of CO2 collected, so, 3.65g17.6g*100=20.7 percent