16. in what kind of reaction does a single chemical compound break apart to form smaller products?
a decomposition reaction
single repalcement
b. synthesis reaction
precipitate reacton

A) Decomposition reactions:

Explanation:

When single chemical compound break apart to form smaller products reaction is called decomposition reaction.

Decomposition reaction:

It is the reaction in which one reactant is break down into two or more product.

AB → A + B

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

Na + Cl →  NaCl

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

Precipitation reaction:

When two solution containing salts are combined produced the precipitate of insoluble salt

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.