Select the correct answer. Which statement best describes how chemical equations demonstrate conservation of mass?

A.
The number of reactants is the same as the number of products.
B.
The compounds are the same on each side of the reaction.
C.
The number of atoms of each element is the same on each side of the equation.
D.
The state of matter is the same on each side of the equation.

C. The number of atoms of each element is the same on each side of the equation.

Explanation:

The conservation of mass states that the initial mass must be equal to the final mass or the mass of reactants must be equal to the mass of the products.

In a balanced chemical equation, the number of atoms of each element must be equal in both sides of the equation (reactants and products). The mass of the compound is the molar mass multiplied by the number of moles presented. And the molar mass will be the sum of the molar mass of each atom multiplied by its quantity in the compound.

Thus, because the number of atoms of each element is the same on each side of the equation it's proved that the mass is conserved.