How many tablets of antacid would be needed?

Question

A normal person produces about 2.2 L of gastric juices during the course of a day. If these fluids contain 3.4 g HCl per liter, how many tablets of antacid, containing 425 mg of Al(OH)3 each, would be needed to neutralize all of the gastric acid produced in one day?

Give your answer in whole tablets.

Example: If your calculation shows that 5.128 tablets are needed then put 6, since the pharmacy won't sell you 0.128 tablets!

Answer 1

2.2 litres @ 3.4 g HCl / litre = 7.48 g of HCl

3 HCl (@36.46 g/mol)   & 1 Al(OH)3  (@ 78.00g/mol)-->

needed to neutralize all of the gastric acid:

7.48 g HCl @ 78 g Al(OH)3 / (3)(36.46g HCl) = 5.33 grams of Al(OH)3

5.33 grams of Al(OH)3 @ 1 tablet / 0.425 grams = 12.55 tablets

your answer is 13 tablets