Question

A Rolaids tablet contains calcium for neutralizing stomach acid. if a Rolaids tablet neutralizes 24.65ml of 0.547m hydrochloric acid, how many milligrams of calcium carbonate are in a Rolaids tablet?​

Answer 1

There are 674 mg of calcium carbonate in a Rolaids tablet

Further explanation

Reaction

CaCO₃ + 2HCl ⇒ CaCl₂ + CO₂ +H₂O

V HCl = 24.65 ml

M HCl = 0.547

mol HCl :

$\tt 24.65\times 0.547=13.48~mlmol$

ratio mol CaCO₃ : HCl = 1 : 2, so mol CaCO₃ :

$\tt \dfrac{1}{2}\times 13.48=6.74~mlmol=6.74\times 10^{-3}~mol$

mass of CaCO₃ (MW=100~g/mol) :

$\tt 6.74\times 10^{-3}\times 100=0.674~g=674~mg$