Question

Different manufacturers claim to have the best antacid. Which of the following tablets would neutralize the most acid for the money?

A. Rolaids (550 mg CaCO3 and 110 mg Mg(OH)2 per tablet) – 150 tablets for $9.44

B. Tums (500 mg CaCO3 per tablet) – 150 tablets for $5.49

C. Phillips (1200 mg Mg(OH)2 per 15 mL) – 769 mL for $9.99

Show all work to get full credit and circle your final answer. You may need to write balanced chemical equations…

Answer 1

CaCO3 + 2HCl ----> CaCl2 + H2O + co2

Mg(OH)2 + 2HCl ----> MgCl2 + 2H2O

MOLARMASS OF cAco3 = 100.0869 g/mol

a. nO of moles of CaCo3 = 0.55/100.0869 = 0.0055 mole.

molarmass of Mg(OH)2 = 58.3197 g/mol

no of moles of Mg(OH)2 = 0.11/58.3197 = 0.0019 mole

No of moles of Acid neutralised = (0.0055+0.0019)*4 = 0.0296 mole per tablet.

amount of acid neutralized = 0.0296*150 = 4.44 mole per $9.44

per one dolar = 4.44 / 9.44 = 0.47 mole per dolar.

b. nO of moles of CaCo3 = 0.5/100.0869 = 0.005 mole.

No of moles of Acid neutralised per tablet = 0.005*2 = 0.01 mole.pertablet

amount of acid neutralized = 0.01*150 = 1.5 mole

per one dolar = 1.55 / 5.49 = 0.28 mole per dolar.

c. no of moles of Mg(OH)2 = 1.2/58.3197 = 0.0206 mole

No of moles of Acid neutralised per 15 ml = 0.0206*2 = 0.412 mole.

No of moles of Acid neutralised per 769 ml = 0.412*769/15 = 21.122 mole

per one dolar = 21.22 / 9.99 = 2.124 mole per dolar

so that , C is the best drug