Ch 23
Section 4
Reaction Rates and Energy
Chemical reactions and
energy
  All chemical reactions release or absorb energy.
  This energy can take many forms, such as heat,
light, sound, or electricity.
  Chemical bonds are the source of this energy.
  Bonds breaking or forming
Activation energy
  In order for a reaction to take place there must be
enough energy present to start the reaction; this
energy is called activation energy.
  All reactions require different amounts of activation
energy.
Exergonic reactions
  Exergonic reactions- chemical reactions that release
energy.
  Ex: glow sticks, heat packs, rocket fuel.
Exothermic reaction
  Exothermic reaction- when the energy given off in a
reaction is in the form of heat.
  Ex: burning of wood or dynamite exploding.
Endergonic reactions
  Endergonic reaction- chemical reaction that
absorbs energy.
  Ex: electroplating and cold packs
Endothermic reactions
  Endothermic reaction- When the energy needed is
in the form of heat.
  Ex: cold pack
Catalysts
  Catalysts- speeds up a reaction without changing
itself.
  When you add a catalyst to a reaction, the mass of
the product that is formed remains the same, but it
will form more rapidly.
Inhibitor
  Inhibitor- used to slow down chemical reactions.
  Ex: use of preservatives in food to stop them from
spoiling