Rates of Chemical Reactions

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Rates of Chemical Reactions

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2

• Kinetics - the study of reaction rates
• The rate of a reaction is how quickly reactants
  turn into products

3
Collision Theory

• Chemical reactions occur when bonds are broken,
  the atoms rearranged, and new bonds formed
• particles must collide for this to happen
• The more propercollisions that occur, the
  faster the reaction
• Collision theory - the rate of a reaction is
  affected by 4 factors concentration, surface
  area, temperature, and catalysts.

4
Concentration

• Measure of the amount of that substance in a
  given unit of volume
• a high concentration of reactants means there are
  a lot of particles per unit volume - more
  particles available for collisions.More
  collisions more products in a certain amount
  of time
• Increase in concentration increases the rate of
  reaction
• What does a decrease mean?

5
Surface Area

• When one reactant is a solid, the reaction rate
  can be increased by breaking the solid into
  smaller pieces.
• More surface area is exposed
• Increase in surface area increases collisions
  higher reaction rate

6
Temperature

• Temperature is the measure of the energy of the
  particles motion
• Increase in temperature increases rate of
  reaction
• Particles at a higher temperature move faster,
  resulting in more collisions and a higher rate of
  reaction

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Catalysts

• Substances that speed up a chemical reaction
• increases the rate of reaction, but is not
  involved in the reaction (it does not chemically
  change)
• Lowers the activation energy - decreases the need
  for collisions to be so energetic, resulting in
  the formation of more product