Question

in atomic theory, new substances are formed when the atoms of other substances are rearranged. in this kind of change, the total number of atoms is conserved. an example of this is shown in the diagram below. there are six atoms both before and after the arrow. which statement below is also true of the rearrangement of atoms? ○a. the number of substances is conserved. ○b. the number of substances increases. ○c. the amount of matter is conserved. ○d. the amount of matter decreases.

Explanation:

• Option A: In a chemical reaction (atom rearrangement), the number of substances can change. For example, in the given diagram, there are 3 substances on the left - hand side (reactants) and 2 substances on the right - hand side (products). So, the number of substances is not conserved.
• Option B: There is no general rule that the number of substances must increase. It depends on the specific reaction. In the given example, the number of substances decreases (from 3 to 2).
• Option C: According to the law of conservation of mass (which is related to the conservation of atoms in atomic theory), the amount of matter (mass) is conserved in a chemical reaction (atom rearrangement). Since atoms are conserved (given in the problem statement) and atoms have mass, the total mass (amount of matter) is conserved.
• Option D: The amount of matter does not decrease in a chemical reaction (atom rearrangement) as atoms are conserved. Atoms have mass, so the total mass (amount of matter) remains the same.

Answer:

C. The amount of matter is conserved.