The concept of catalyst in high school chemistry
The catalyst is selective, that is, a catalyst that catalyzes only one or more chemical reactions and does not catalyze all chemical reactions. However, a chemical reaction of the catalyst may be a variety of, such as hydrogen peroxide to produce oxygen in the reaction, in addition to the use of manganese dioxide as a catalyst, you can also use copper oxide, iron oxide as a catalyst. Building on the use of cement, red brick powder also catalyze the decomposition of hydrogen peroxide.
Since the catalyst can only change the chemical reaction rate, the catalyst can not increase the mass of the product. The quality of the product depends only on the quality of the reactants.
The "chemical properties" and "quality" did not change before and after the reaction, indicating that the chemical properties and quality of the catalyst before and after the chemical reaction must remain unchanged, but the physical properties may change. Therefore, it can not be said that the nature of the catalyst itself did not change before and after the reaction.
Change "has a double meaning, that is," speed up "or" slow down. "Some students believe that the role of catalyst is to speed up the chemical reaction rate.In fact, the catalyst also has positive and negative points, positive catalyst can speed up the chemical reaction rate, such as Enzymes in the human body can speed up the digestion of food and so on; and negative catalyst can slow down the rate of chemical reactions, such as rubber products in the antioxidant.
In the chemical reaction can change the chemical reaction rate of other substances, and its own quality and chemical properties before and after the reaction did not change the material called catalyst (also known as catalyst).
