find the correct mmol HCl / mg sample,The difference between the millimoles of HCl used to dissolve the sample and the millimoles of NaOH required to titrate the residual acid, when divided by the antacid sample mass in milligrams, is the number you are seeking.

Calculate the volume of diluted HCI needed to neturalize each tablet. Brand Active Ingredients (per tablet) Tums 500 mg calcium carbonate 675 mg calcium carbonate Rolaids 135 mg magnesium hydroxide Molar mass (g/mol) Calcium carbonate (CaCO3) 100.087 Magnesium hydroxide (Mg(OH)2) 58.320 Data analysis for titration. Mass of Volume of crushed HCI used tablet to dissolve Molarity of Volume of NaOH Molarity of mmol HCI / mg dissolved HCI samples used (mL) NaOH sample in HCI (g) (mL) Trial 1 0.191 0.00785 x 5.00 0.300 22.38 0.100 Trial 2 0.191 5.00 0.300 22.38 0.100 0.00785 Trial 3 0.191 5.00 0.300 22.38 0.100 0.00785