The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. ... A product is a substance that is present at the end of a chemical reaction.

✓ Reactants

✓Reactants

✓ product

Explanation:

The substance(s) to the left of the arrow in a chemical equation are called

A is a substance that is present at the start of a chemical reaction.

A is a substance that is present at the end of a chemical reaction.

Reactants are substances that undergo chemical reaction and are present at the beginning of the reaction and are consumed during the process of the reaction to form a product.

2H2 + O2 >2H2O

Here H2 and O2 are Reactants while water H2O is the product ( water)

Products are species that are produced after the chemical reaction have taken place.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.