A single replacement reaction will only happen if the solid metal is more or less reactive than the metal that is dissolved in solution.

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.

that's what i got you can count the number of atoms

ok whats the question if not i cannot you i need question and need a thing to answer