Question

What is the meaning of 20% impure calcium carbonate required?

Answer 1

Answer:

The mass of pure Calcium carbonate is :

80/100 × 25 = 20g

Equation for the reaction is :

CaCO₃ (s) + 2HCl (aq) —> CaCl₂(s) + CO₂(g) + H₂O(l)

The mole ratio of Calcium carbonate and the CO₂ liberated is 1 : 1

Moles of Calcium carbonate = mass of calcium carbonate / molar mass

Molar mass of Calcium carbonate = 100

Moles = 20/100 = 0.2 moles

Moles of CO₂ = 0.2 moles

Molar gas volume at NTP is :

1 mol = 22.4 litres

0.2 moles =?

0.2 × 22.4 = 4.48 litres

CO₂ liberated is 4.48 litres

Answer 2

Answer:

A 20% impure sample of calcium carbonate indicates a calcium carbonate sample with 80% purity.

Generally, the calcium carbonate sample that is used is mined and not synthesized. The main source of calcium carbonate is limestone that is mined from the ground. This limestone consists of a mixture of magnesium and calcium carbonate salts. it is not easy to separate both these salts, and is often ignored. Thus, the final purity of the calcium carbonate sample is based on the initial impurity of the limestone sample.