Which of these is an example of a description of speed?
An airplane traveled west from New York to Los
Angeles.
A train traveled east at 200 mph from Albuquerque to
Dallas.
The average Olympic sprinter runs 8 m/s.
An apple fell from the tree and then rolled 1 m north.

Probably B or C bc it seems right. Hope this helps

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.