Chemical Reaction Rates & CatalystsReaction RatesReaction rates are affected by temperature, concentration, and surface area. As the temperature of a substance increases, the kinetic energy increases. At higher temperatures, more collisions have the necessary energy to occur, so the reaction rate increases. The concentration of a substance is the amount of that substance in a given amount of a solvent, such as water. A higher concentration means more collisions. If the probability of a favorable collision increases, so does the reaction rate. increased reaction rateCatalysts Catalysts play an important part in many chemical processes. A catalyst is a substance that speeds up the rate of a chemical reaction by lowering its activation energy. A catalyst does not get permanently changed and does not get used up in the reaction. Catalysts are important in many industrial chemical applications, as well as in biochemical reactions. reactant(substrate)enzymeenzyme-substratecomplex“free” enzyme- can be reusedproductsactivationenergy isloweredreactantsproductsenergyreaction progresscatalystaddedHClHClconcentrated HCldilute HClmarbleIncreasing the surface area of solid reactants exposes more reactant particles to each other, which in turn increases the rate of reaction. Conversely, lowering the temperature, concentration, or surface area will slow down a chemical reaction. © Copyright NewPath Learning. All Rights Reserved. 94-4866Visit www.newpathlearning.com for Online Learning Resources.increased reaction rateIn biological systems, the most common catalysts are protein molecules, called enzymes. Enzymes act as catalysts in virtually all chemical reactions within cells.HClHClincreased reaction ratesmall surface arealarge surface arealow heathigh heatmore surface areaReaction rates are affected by temperature, concentration, and surface area. As the temperature of a substance increases, the kinetic energy increases. At higher temperatures, more collisionshave the necessary energy to occur, so the reaction rate increases. Thhhhhhhhhhheeeeeeeeeeeeee ccccccccconnccccccccccceeeeeeeeeennnnnnnnnnnnnntttttttttrraaaaaaaaaaaatttttttttttiiiiiiiiiiiiooonnnnnnnnnnnnnn of a substanceeee iiiiiiiiisssssssssss the ammmmmmmmmmoooooooooooouuuuuuuuuuuuuuuunnnnnnnnnnnntttttttttt of that substtaaaaaaaaannnnnnnnnnnnnnnnnccccccccccccceeeeeeeeeeeeeeee in aaaaaaaaaaa gggggggggggggggiiiiiiiiiivvvvvvvvvvvven amount of aaaaaaaaaaaaaa ssssssssssssooooollllllllllllvvvvvvvvvvvvvvveeeeeeeeeeennnnnnnnnnnnnnnnnnttt,, suchhhhhhhhh as water. 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