Question

20 g of sodium bicarbonate is added to 15 g of hydrochloric acid. The mass of only sodium chloride
and water is found to be 18.213 g. Assuming the validity of law of conservation of mass, calculate the mass of carbon dioxide evolved.​

Answer 1

Explanation:

Na

2

CO

3

+2HCl⟶2NaCl+H

2

O+CO

2

Law of conservation of mass- It states that for any closed system, the mass of the system always remain constant over time, as mass of system cannot change. Therefore, (mass of Na

2

CO

3

+ mass of HCl) should be equal to (mass of residue + mass of CO

2

)

Mass of Na

2

CO

3

=4.2 g

Mass of HCl=10 g

Mass of residue =12 g

Mass of CO

2

=2.2 g

∴ Mass of Na

2

CO

3

+ Mass of HCl=14.2 g

and Mass of residue + Mass of CO

2

=14.2 g

Therefore, they follow law of conservation of mass