  The minimum amount of energy needed to start a chemical reaction  All chemical reactions require a certain amount of activation energy to get started Activation Energy

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  Factors that affect rates of reaction include:  Surface area  Temperature  Concentration  Presence of catalysts and inhibitors Rates of Chemical Reactions

  When a chunk of solid substance reacts with liquid or gas, only the particles on the surface of the solid come in contact with the other reactant  If you break the solid into smaller pieces, more particles are exposed and the reaction happens faster  When can this be useful?  Chewing your food breaks it into smaller pieces that your body can digest more easily and quickly! Surface Area

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  Increase the temperature=increase rate of reaction  When you heat a substance, its particles move faster  Come in contact more often  Faster-moving particles have more energy. Therefore, causes more particles of the reactant to get over the activation energy hill Temperature

  The amount of a substance in a given volume  Adding a small spoonful of sugar to lemonade will make it sweet but adding a large spoonful of sugar will make it sweeter  Supplies more particles to react Concentration

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  Material that increase the rate of a reaction by lowering the activation energy  Not considered reactants because catalysts are not permanently changed  Enzymes=biological catalysts  Enzymes provide a surface for the reaction to take place  By bringing the reactant molecules close together, it lowers the activation needed to get the reaction started Catalysts

 Enzymes

  Sometimes a reaction is more useful when it can be slowed down rather than sped up  Inhibitors are used to decrease the rate of reaction  Prevent reactants from coming together  Preservatives added to food act as inhibitors to prevent food products from spoiling or becoming stale Inhibitors