Q:Chemical reaction plus catalyst on the △ H no effect

Since the catalyst only acts to reduce the activation energy of the reaction and accelerate the reaction rate, it does not participate in the reaction, so that the energy difference between the product and the reactant is not affected,

Q:I know that a species that does not appear in the chemical equation may also affect the rate of a reaction - e.g. a catalyst. But does that mean the catalyst can be present in the rate equation, and if so are catalysts always present in the rate equation?

Yes, a catalyst can be included in a rate law. That's because, most reactions occur in a series of step and the rate is based on the rate determining step, which is the slowest step. A catalyst may be a reactant in the rate determining step, and a product in a subsequent step. Therefore, the catalyst is not included in the overall reaction. But a catalyst need not always be in the rate law. The rate law is usually based on the rate determining step. ========== Follow up =========== In the free response questions on the AP chemistry exam there has been at least one case where a rate law included a catalyst( 2002D). Brown and LeMay always include at least one in their examples, and I always cover this situation when I teach rate laws and mechanisms in AP chemistry. Here is one comment: Other examples of species not in the balanced reaction occurring in the rate law would include catalysis, where a catalyst does not normally appear in the balanced reaction but does appear in the rate law. www.chem.arizona.edu/~salzmanr/48... Consider this generalized reaction which is catalyzed by M A + B --C A + M --Q ... slow Q + B --C ... fast M is the catalyst, and Q is the intermediate. The slow, or rate determining step, depends only on the concentrations of A and M, the catalyst. So even though the overall reaction does not include, M, the rate law does. Rate = k[A][M]

Q:In the chemical calculation, the quality of the catalyst should not be counted before and after the reaction

It is not the same .. because the quality of the catalyst will not change .

Q:What makes an enzyme a catalyst?

It lowers the energy of activation for a specific chemical reaction. Best wishes.

Q:What is the difference between an enzyme catalyst in a living body and a catalyst in chemistry?

enzyme susceptibility inactivation Chemical catalyst under certain conditions, due to poisoning and loss of catalytic capacity; and enzyme than the chemical catalyst is more fragile, more volatile activity. Any factor that makes the protein degenerate (to strengthen the acid, alkali, high temperature, etc.), can make the enzyme completely lost activity.

Q:The catalyst before and after the reaction of the quality and nature of the same, does it mean that a little catalyst can be all the substrate reaction? Such as: one gram of MnO2 can reflect the infinite H2O2?

Catalyst before and after the reaction of the same quality,

Q:Please make it simple because I need it for school and please give to examples for the second part Thanx :D

A catalyst is a substance that speeds up the rate of a chemical reaction with itself being chemically unchanged at the end of the reaction. They are useful as they help to lower the minimum amount of energy needed ( also known as activation energy) to start the reaction. Hence, by lowering the activation energy of the reaction, they help to speed up the rate of reaction. For example, in the Haber process for the manufacture of ammonia, the catalyst iron is added to speed up the rate of reaction between hydrogen gas and nitrogen gas. Otherwise, the reaction would have proceeded much more slowly. Another example is the catalyst nickel used in the manufacture of margarine and vanadium (V) oxide for manufacturing sulfuric acid. As catalyst remain chemically unchanged after a reaction, they can be reused again and hence, they are required in minute amounts. An example is the washing powder used in washing clothes, they help to remove food stains by digesting the proteins in food. They can be reused after each reaction and hence, you do not need to add in the whole packet of washing powder but only a few spoonful.

Q:Just something I've always wondered about...

activation energy has got nothing to do with this. the main reason that the transition metal oxides are catalysts is that they have vacant d orbitals. the reagents are adsorbed on the metal surface and the d orbitals serve as a sort of clamp between the substrates and reagents. for example if you consider the hydrogenation of ethylene in palladium catalyst here the d orbitals lead to syn addition of hydrogen by clamping the pi electron cloud . this is a sort of chemisorption.

Q:Will the catalyst change in the chemical reaction?

In fact, there are two kinds of catalyst mechanism, one is not a chemical reaction, the reaction did not occur throughout the chemical reaction, the catalyst did not change; one is involved in the reaction process, but the final production of the catalyst, which The class reaction generally occurs in a stepwise chemical reaction.

Q:The concept of catalyst in high school chemistry

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.