For beginners in chemistry, the concept of Moore is really not easy to understand. You can explain the mole from the number of molecules of a substance. The redox reaction needs to be explained by the change of valence. In a word, chemistry is different from mathematics and physics. It is an experimental subject, and it needs to remember a lot of chemical reactions and concepts before it can be understood.

Someone once said that chemistry and biology are "stupid" sciences, that is to say, you can't learn chemistry and biology well just by being smart and not trying to remember a lot of knowledge.