Question

which statement correctly explains how matter is conserved in chemical reactions? (1 point)

the number of molecules in the reactants is always equal to the number of molecules in the products.

the number of reactants is always equal to the number of products.

the number of atoms in the reactants is always equal to the number of atoms in the products.

the states of matter of the reactants are always the same as the states of matter of the products.

Explanation:

To determine the correct statement about conservation of matter in chemical reactions, we analyze each option:

• The first option is incorrect because the number of molecules can change (e.g., in $\ce{2H_2 + O_2 -> 2H_2O}$, 3 reactant molecules form 2 product molecules).
• The second option is incorrect as "number of reactants" (types) isn't conserved; reactions can form new substances.
• The third option is correct. The Law of Conservation of Mass (or matter) states that atoms are neither created nor destroyed in a chemical reaction, so the number of atoms in reactants equals that in products.
• The fourth option is incorrect because states of matter (solid, liquid, gas, aqueous) can change in reactions (e.g., $\ce{H_2O(l) -> H_2O(g)}$ in evaporation, or in chemical reactions like $\ce{2H_2(g) + O_2(g) -> 2H_2O(l)}$).

Answer:

The number of atoms in the reactants is always equal to the number of atoms in the products. (The option with this statement, typically the third radio button option in the given choices)