What is the full name of the compund CuSO4?
Please can you help me? (✿◡‿◡)

CuSO4 is Copper Sulphate.

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.

its first and third is your answer i did the qustion the fourth isnt right