When chemical reactions occur, the physical and chemical properties of the reactants are the same as the properties of the productsthe physical and chemical properties of the products are different from the reactantsthe compounds can be separated by physical meansa phase change takes place

the physical and chemical properties of the products Are different from the reactants. This causes the changes to be seen, physical changes and chemical.

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.