Question

How do you calculate the percentage of calcium in calcium carbonate, $CaC{O_3}$?

Answer 1

The mass percentage is defined as the way of representing the concentration of the element in the compound. The mass percentage is calculated by dividing the mass of the element by the total mass of the compound multiplied by 100. It is represented as (w/w)%.

Complete step by step answer:
The mass percentage of the compound or atom is defined as the mass of the atom divided by the total mass of the compound multiplied by 100.
The formula to calculate the mass percentage of the compound or atom is shown below.
$mass\% = \dfrac{{mass\;of\;component}}{{Total\;mass\;of\;component}} \times 100$
For any solution, the mass % of the solute is calculated by the formula as shown below.
$mass\% = \dfrac{{mass\;of\;solute}}{{Total\;mass\;of\;solution}} \times 100$
The atomic mass of calcium is 40.078 g.
The molecular mass of $CaC{O_3}$ is 100.085 g.
The atomic mass in the atom is the sum of the masses of protons, neutrons and electrons.
The molecular mass of the compound is calculated by adding the atomic mass of the atom present in the compound and multiplying the number of atoms with the atomic mass.
To calculate the mass percent of calcium, substitute the value of atomic mass of calcium and atomic mass of calcium carbonate in the given formula.
$\Rightarrow mass\% = \dfrac{{40.078g}}{{100.085g}} \times 100$
$\Rightarrow mass\% = 40.04\%$
Therefore, the percentage of calcium in calcium carbonate is 40.04%.

Note:
In the given question, the mass of the components are not given, therefore atomic mass or molecular mass of the compound is used. When the mass of the compound is provided then the value is used to calculate the mass percentage.