What is the atomic mass of calcium carbonate?

To answer this question, we must first understand the chemical formula of calcium carbonate. Next, we must understand the individual mass of each atom present in that formula. Finally, we must calculate the quantity of each type of atom present before determining the atomic mass of calcium carbonate.

Based on our knowledge of chemical formulas, we all know that the chemical formula for Calcium Carbonate is ${\mathrm{CaCO}}_3$_.

Now, individually we know that the atomic mass of Calcium is 40, Carbon is 12 and for that of Oxygen is 16.

Now, we will see the number of atoms for each element present, i.e., Calcium has 1 atom, Carbon has 1 atom and Oxygen has 3 atoms present in the formula. So, we will multiply by the number of atoms present for each element.

So, the atomic mass will be:

1$\times$40 + 1$\times$12 + 3$\times$16= 40 + 12 + 48

So the atomic mass will be 100g.

Hence, the correct answer is option (a).