Question

The molecular weight of calcium carbonate $CaC{{O}_{3}}$ is:
A. 80
B. 90
C. 100
D. 110

Answer 1

The molecular mass is the mass of a given molecule. To calculate the molecular weight of calcium carbonate we can add up the molecular weights of the elements constituting calcium carbonate which are calcium, carbon and oxygen multiplied with their stoichiometry.

Complete answer:
The sum of the atomic masses of all atoms in a molecule helps us calculate the molecular mass of any substance. Its unit is grams per mole. For example, the molecular weight of water, which has two atoms of hydrogen and one atom of oxygen, is 18 g/mol that is 16+2 as there is one oxygen and two hydrogens in a water molecule.
Now, to calculate molecular weight of calcium carbonate we can add up the molecular weights of the elements calcium, carbon and oxygen multiplied with their stoichiometry as done in the previous example.
We know, molecular weight of calcium, carbon and oxygen which are as follows:
Calcium = 40
Carbon = 12
Oxygen = 16
To calculate weight of calcium carbonate we will add them up,
Calcium carbonate $=40\times 1+12\times 1+16\times 3$
= 100 g/mol
So, the correct answer is “Option C”.

Note: Calcium carbonate is used as a dietary supplement when the amount of calcium taken in the diet is not enough. Calcium is a very important element as it is needed by the body for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used in Oils,Plastic/Rubber,Cement, Glass,Steel,Paper, construction industries.