Introduction What is energy ENERGY ENERGY Sound is

Introduction: What is energy? ENERGY

ENERGY? ? Sound is energy!

ENERGY? ? Light is energy!

ENERGY? ? ? Chemical Reactions are Energy Chemical Reaction

ENERGY? ? ? Heat is energy

BONDS BREAK AND FORM DURING CHEMICAL REACTIONS. � Chemical reactions change substances into different ones by breaking and forming chemical bonds. � Reactants are changed during a chemical reaction � Products are made by a chemical reaction.

BONDS CONTAIN ENERGY � Bond energy is the amount of energy that breaks a bond. – – – Energy is added to break bonds. Energy is released when bonds form A reaction is at equilibrium when reactants and products form at the same rate. CO 2 + H 2 O H 2 CO 3

CHEMICAL REACTIONS RELEASE OR ABSORB ENERGY. � Activation energy is the amount of energy that needs to be absorbed to start a chemical reaction.

CHEMICAL REACTIONS RELEASE OR ABSORB ENERGY. � Exothermic (exergonic) reactions release more energy than they absorb. – Reactants have higher bond energies than products. – Excess energy is released by the reaction.

CHEMICAL REACTIONS RELEASE OR ABSORB ENERGY. � Endothermic (endergonic) reactions absorb more energy than they release. – Reactants have lower bond energies than products. – Energy is absorbed by the reaction to make up the difference.

PRACTICE � Think of 7 -10 chemical reaction and determine if they are exothermic or endothermic � Draw an energy diagram for a sprinter

HOMEWORK �Complete Chapter 2 Review numbers 1 -9 (support why you picked each answer)

APPLICATION � Draw an energy diagram for each reaction you determined in the Practice

CLOSING All life processes require energy