Rates of Reaction

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Rates of Reaction

• Mrs. Kay

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Rate of reaction

• The time it takes for a reaction to take place.
• The time needed for a certain amount of reactants
  to become a certain amount of product

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Factors of Rates

• Concentration
• Surface area
• Temperature
• Using catalysts

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Concentration

• Is the amount of substance per volume.
• If there is more concentration, then there is
  more chance of collision.
• More collisions means faster reaction rate
• Picture shows 8 successful reactions

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• If there is less concentration, then less likely
  to have collisions
• Less collisions means lower reaction rate
• Picture show 3 successful reactions

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Surface Area

• The area of an object (length x width)
• Smaller bits will react faster than bigger bits
• Ex small piece of wood burn better than large
  logs

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• The more surface area there is, the more places
  for collision and reactions to take place, so
  faster reaction rate
• The less surface area there is, the less places
  for collisions and reactions to take place, so
  the lower the reaction rate

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Temperature

• Remember thermal energy!
• If I take energy away (lower the temperature)
  then there will be less movement and less
  collisions.
• Lower temperature means lower reaction rate

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• If I increase the temperature, then I increase
  the energy and more collisions occur
• More collisions means faster reaction rate

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Using Catalysts

• Catalysts - a substance that increases the rate
  of a reaction but is not itself changed by the
  reaction.
• Ex like adding a chemical or even by stirring
  the mixture!

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Acids and Bases

• Science 10

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Acid

• In 1884 the Swedish chemist Svante Arrhenius
  defined an acid as a substance that produces
  hydrogen ions in solution, H (aq).
• For example, HCl (aq), hydrochloric acid is an
  ionic compound that dissolves in water, splitting
  into H (aq) and Cl (aq) ions.
• pH less than 7
• Turns red litmus red, and blue litmus red

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Bases

• Arrhenius also defined a base as a substance that
  produces hydroxide ions in solution, OH (aq).
• An example of a base is sodium hydroxide, NaOH
  (aq). Sodium hydroxide forms OH ions in
  solution.
• pH greater than 7
• Turns blue litmus blue, and red litmus blue

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Neutral

• pH is 7
• Water is a common neutral substance.