Question

4. A piece of limestone (CaCO3) with an initial mass of 3.24 g is placed in 100 mL of a HCl solution. The

calcium carbonate reacts with the hydrochloric acid solution to yield calcium chloride, carbon dioxide, and
water. Once this reaction goes to completion there is still 2.24 g of excess limestone left in the solution.
Write a balanced equation to represent this reaction and find the molarity of the hydrochloric acid

Answer 1

Step-by-step explanation:

The balanced chemical equation for the reaction between calcium carbonate (CaCO3) and hydrochloric acid (HCl) is:

CaCO3 + 2 HCl → CaCl2 + CO2 + H2O

According to the problem, 3.24 g of calcium carbonate reacted with excess hydrochloric acid, leaving 2.24 g of excess limestone in the solution. This means that 3.24 - 2.24 = 1 g of calcium carbonate reacted with the hydrochloric acid. We can use this information to calculate the number of moles of calcium carbonate that reacted:

1 g CaCO3 / 100.09 g/mol CaCO3 = 0.00999 mol CaCO3

Since the balanced chemical equation shows that 1 mole of calcium carbonate reacts with 2 moles of hydrochloric acid, we know that 0.01998 moles of hydrochloric acid reacted. We can use this information to calculate the molarity of the hydrochloric acid solution:

Molarity = moles of HCl / volume of solution

Molarity = 0.01998 mol / 0.1 L

Molarity = 0.1998 M

Therefore, the molarity of the hydrochloric acid solution is 0.1998 M.