My concern here is , in determining the mass % of CaCO3, do i used the mass of the tablet given (0.825g ) in term of:= 0.750g caco3 per tablet / total mass *100 ? given as total mass or do i used the molar mass. 2) is 0.750g caco3 my theoretical value?

2. A tums tablet pulverized (powdered) and 0.4265 g of this power was mixed with 9.00 mL 1.000 M HCl. This mixture was back-titrated with 0.1000 M NaOH with phenolphthalein as indicator. It required 8.25 mL of 0.1000 M NaOH to reach the end point. Compute % CaCO3 in the tums sample and % error. Guide to calculations- Analysis of an Antacid back titration Mass of one tablet = 0.825 g g of CaCO3 in one tablet = 0.750g as per the label Theoretical % of CaCO3 = g of powder sample used in your titration = g g of CaCO3 # 4 = g mL of NaOH used in titration (from experiment) = L M of NaOH = M # mol NaOH used = (# 6) x (# 7) = mol # mol HCl left unreacted = # 8 (1:1 Ratio) # mol HCl added = [Volume of HCl added in L x M of HCl used] =______mol # mol HCl reacted with the CaCO3 in the powdered sample = [#10 #8] # mol CaCO3 in the powdered sample = [mol HCl x ] = [# 11 x ] # g CaCO3 in the powdered sample = #12 x 100.09g/mol % CaCO3 in your sample ( experimental ) = (#13 / #4) x 100 = % % Error = (#3 #14 / # 3) x 100 = %