Endothermic and Exothermic Reactions Notes PDF

Endothermic and Exothermic Reactions Notes External/outsideEndo:_______________ Exo: _____________________ Inside Heat Thermic:__________________ In all chemical reactions, energy is either released or absorbed. This energy can t...

Endothermic and Exothermic Reactions Notes External/outsideEndo:_______________ Exo: _____________________ Inside Heat Thermic:__________________ In all chemical reactions, energy is either released or absorbed. This energy can take many forms: light, sound or electricity. Where does the energy to be released or absorbed come from? When most chemical reactions take place, some bonds in the reactants must be broken. To break chemical bonds, energy must be provided. In order for products to be produced, new bonds must be formed. Bond formation releases energy. One Way to Classify Reactions…All Reactions involve Energy. So, they are either… Endothermic reactions or Exothermic reactions An endothermic reaction is a chemical reaction that requires the ….. addition of heat energy to proceed The reaction absorbs heat from its surroundings. cold Takes in heat for reaction to occur (feels _____________ to the touch because it is taking away your heat). bonds decrease in temperature. Eg. ____________________________ This causes a _________________ breaking releases An exothermic reaction is a chemical reaction that _________________________. energy not Gives off heat for reaction to occur (feels __________________ to the touch because it is giving additional heat to you). bands increase This causes an _______________________ forming in temperature. Eg. _________________________ Examples: Liquid Icepacks (reaction between water and ammonium nitrate) Endo Photosynthesis Endo Burning of wood EXO Explosion of dynamite fXO Rusting EXO  Overall Energy Changes In Reactions break In endothermic reactions, the energy needed to ________________ existing bonds is greater than the energy released when new bonds are formed. formed is greater In an exothermic reaction, the energy released when new bonds are _____________ than the energy taken in breaking the existing bonds. Reaction Profiles Diagrams In reaction profile diagrams, the energy change in a reaction, is the differencebetween the reactants and products. ___________________ Activation Energy: the minimum amount of energy that must be applied to start a chemical reaction. Without this energy being applied, a reaction will not occur. Examples: - Must apply enough strike energy to start a match to to tip the mater burn won't · Gasoline air , burn in apply unlessat(spark speeds up Catalyst: substance that ____________________the rate of a chemical reaction without being used up _______________________________________________ in the reaction itself -reduce energy required lowers -________________________activation energy eg. Enzymes