For real
select all of the mediums that sound waves can travel through:

vacuum

gases

liquids

solids

I belive the answer is gases, liquids, and solids.

Explanation:

The reason I say this is because a vacuum is an empty void of space and time, nothing is there so I believe no sound should be able to penetrate through it.

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.