Chemists want to control not only what comes out of a chemical reaction, but how fast the reaction occurs. For example, scientists are working to slow down the depletion rate of the ozone in the upper level of our atmosphere, so we stay protected from harmful UV rays.
The rate of the chemical reaction of a nail rusting is slow compared to how fast baking soda reacts with vinegar. Different factors affect the speed of the reaction, but the main idea is that the more collisions between particles, the faster the reaction will take place.
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A catalyst can also slow down a reaction. A catalytic promoter increases the activity, and a catalytic poison (also known as a negative catalyst, or inhibitor) decreases the activity of a reaction.
Catalysts offer a different way for the reactants to become products, and sometimes this means the catalyst reacts during the chemical reaction to form intermediates. Since the catalyst is completely regenerated before the reaction is finished, it’s considered ‘not used’ in the overall reaction.
A catalytic converter, like the one you’ll find on cars, takes harmful molecules that come out of the engine like hydrocarbons, carbon monoxide, and nitrogen oxide and converts it into harmless molecules that don’t hurt the environment. The catalyst in these is usually platinum and palladium and it converts carbon monoxide to carbon dioxide, hydrocarbons into carbon dioxide and water, and nitrogen oxide into nitrogen and oxygen, stuff we use to breathe in our atmosphere. The picture of the one in the upper left is from a diesel engine, and the image in the lower right is the kind you’ll find under your car connected to the tailpipe.
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