NO FILES PLZ HELP When a solid produced by a chemical reaction separates from the solution it is called...

a precipitate.
a molecule.
b. a reactant.
d. the mass of the product.

a. Precipitate

Explanation:

solids can precipitate out of the solution and be left over after the reaction. reactants are incorrect because they are reacted to cause the reaction. b and d are also irrelevant terms.

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.