Which statement is true regarding a chemical reaction?

Question

1. The total number of atoms does not change, so mass is conserved in the reaction.
2. The total number of atoms changes, so mass is conserved in the reaction
3. Even if the total number of atoms changes, mass may not be conserved in the reaction.
4. Even if the total number of atoms does not change, mass may not be conserved in the reaction.

Answer 1

The true statement regarding a chemical reaction is:

1. The total number of atoms does not change, so mass is conserved in the reaction.

In a chemical reaction, atoms are rearranged to form products from reactants, but the number of each type of atom remains the same before and after the reaction. This is consistent with the law of conservation of mass, which states that mass cannot be created or destroyed in a closed system.