A 2.0L balloon at room temperature (20.0oC) is placed in a refrigerator at 3.0oC. What is the volume of the balloon after it cools in the refrigerator? What would be the final size of the balloon in the example problem above if it were placed in a -18oC freezer?

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.