Question

value: 4 which of the following parts in the chemical formula represents substances that are present at the start of a chemical reaction?
○ a. product
○ b. reactant
○ c. compound
○ d. molecule

Explanation:

To solve this, we analyze each option:

• Option a: Products are the substances formed at the end of a chemical reaction, not the start.
• Option b: Reactants are defined as the substances present at the beginning of a chemical reaction that undergo change.
• Option c: A compound is a type of substance (composed of two or more elements), not specifically related to the start of a reaction.
• Option d: A molecule is a group of atoms bonded together, and it's not specific to the start of a reaction.

So the correct option is b as reactants are the starting substances in a chemical reaction.

Answer:

b. Reactant