During a reaction of ca(oh)2 with carbon dioxide gas, 20g of solid caco3 is formed. calculate the mass of the nahco3 needed to produce the amount of carbon dioxide gas responsible for forming the caco3 precipitation.

Answer 1

Ca(OH)2 + CO2 ==> CaCO3 + H2O
mols CaCO3 formed = grams/molar mass = estimated 0.2 mol.

NaHCO3 + HCl ==> NaCl + H2O + CO2

Looking at the equations, you had 0.2 mol CaCO3 formed, and that was produced by 0.2 mol CO2. From the lower equation, for form 0.2 mol CO2 you need 0.2 mol NaHCO3.

Convert mols NaHCO3 to grams NaHCO3.
That's g = mols x molar mass = ?