CaCO3 + 2HCl - -> CaCl2 + CO2 + H2O In the reaction above, what mass of carbon dioxide is produced when 10 moles of HCl reacts with excess calcium carbonate?

According to the stoichiometry the CO2 formed is 1/2 the moles of H2O. So take the moles of CO2 as 5moles.

n=m/M

Where:

n = mole

m = mass

M = molar mass

Molar mass of CO2 = 44gmol^-1

Therefore mass = 5mol * 44gmol^-1 = 220g