Question

The molecular weight of calcium carbonate $CaC{O}_3$ is:

• A. 80
• B. 90
• C. 100
• D. 110

Answer 1

The correct option is C 100

Molecular weight is the mass of whole molecule.

Steps:- (1) Chemical formula of calcium carbonate $⟶CaC{O}_3$

(2) Mass of Calcium$⟶40$

Mass of Carbon$⟶12$

Mass of Oxygen$⟶16$

(3) Multiply mass of each element by number of atoms of that element.

(4) Add all the masses obtained after multiplication.

$⟶CaC{O}_3$

$=1\times 40+1\times 12+3\times 16$

$=40+12+48$

$=100$.