Middle school chemistry knowledge point summary must memorize

Chemistry is a study of the nature of matter, composition, structure, change, use, production, and the law of change of matter of natural science.

Chemistry and industry, agriculture, daily life, medicine, materials, etc. are very closely linked. For example: coal, oil and natural gas combustion produces carbon dioxide and other substances. The study of chemistry deals with the interrelationships between substances, or the association between matter and energy. Traditionally, chemistry has often been about two substances coming into contact and changing, i.e., chemical reactions, or the process by which one substance becomes another.

These changes sometimes require the use of electromagnetic waves, which are responsible for triggering chemical reactions. But sometimes chemistry doesn't even have to be about reactions between substances. Spectroscopy studies the relationship between matter and light, and these relationships do not involve chemical reactions.