Question

In a ventilated hood in a lab, a student heats barium metal over a flame, and it begins to react with oxygen gas in the air. A white crystalline compound begins to form on the burning barium.

2 Ba (s) + O2 (g) --> 2 BaO (s) = energy

Which statement best describes the reactants and products?

A. Equal numbers of barium atoms are in the reactants as in the products.

B. Fewer overall atoms are in the products than in the reactants.

C. Twice as many oxygen atoms are in the reactants as in the products.

D. More atoms are in the products than in the reactants.

Answer 1

Equal numbers of barium atoms are in the reactants as in the products.

Option A.

Explanation:

The law of conservation of mass states that mass can never be created neither the destroyed. And this law holds good for the chemical reactions except the nuclear reactions.

So, the mass of the reactants in a chemical reaction is equal to the mass of the products. Thus, the mass of barium and oxygen in total is equal to the mass of barium oxide produced.

Also in the balanced chemical reaction, we can see that two moles of barium are present in reactant side, as well as in product side as well. Similarly with the oxygen, two moles are present in both the sides.