QUICK ANSWER
J.J. Thomson's cathode ray experiment was a set of three experiments that assisted in discovering electrons. He did this using a cathode ray tube or CRT. It is a vacuum sealed tube with a cathode and anode on one side.
Answer: During a chemical reaction, matter cannot be created nor destroyed, matter can change form through physical and chemical changes, but through any of these changes, matter is conserved; even though the matter may change from one form to another, the same number of atoms exists before and after the change takes place.
Explanation: <3
A mixture that results when substances dissolve to form a homogeneous mixture is a solution.
Option d: copper.
Because copper is an element, not a mixture.