Question

caco₃(aq) + 2hcl(aq) → cacl₂(aq) + h₂o(l) + co₂(g)

1. how much 0.80 m hcl would be needed to dissolve a caco₃ pearl which weighs 4.0 grams?

Explanation:

Step1: Calculate moles of CaCO₃

Molar mass of CaCO₃ = 40 + 12 + 3×16 = 100 g/mol
Moles of CaCO₃ = $\frac{4.0\ \text{g}}{100\ \text{g/mol}} = 0.040\ \text{mol}$

Step2: Find moles of HCl needed

From reaction: 1 mol CaCO₃ needs 2 mol HCl
Moles of HCl = $0.040\ \text{mol} × 2 = 0.080\ \text{mol}$

Step3: Calculate volume of HCl

Volume = $\frac{\text{moles}}{\text{molarity}} = \frac{0.080\ \text{mol}}{0.80\ \text{M}} = 0.10\ \text{L}$ (or 100 mL)

Answer:

0.10 L (or 100 mL)