FACTORS THAT AFFECT RATES OF REACTION

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FACTORS THAT AFFECT RATES OF REACTION

• Chapter 7.3

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COLLISION MODEL

• States that the rate of reaction is affected by
  the number of collisions of reactant molecules.
• Molecules in a gas or a liquid are constantly
  colliding with each other.

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4 FACTORS

• There are four factors that affect the rate of
  reaction.
• TEMPERATURE
• CONCENTRATION
• SURFACE AREA
• CATALYSTS

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TEMPERATURE

• Higher temperatures increase the rate of a
  chemical reaction because particles move faster
  at high temperatures and this creates more
  violent collisions more often.

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CONCENTRATION

• Higher concentration increase the rate of a
  chemical reaction because there are more
  particles to collide with.

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SURFACE AREA

• A larger surface area increases the rate of a
  chemical reaction because there are more exposed
  particles in the compound.

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CATALYSTS

• A substance that increases a chemical reaction
  but does not get consumed by the reaction.
• Therefore it is not considered a reactant or
  product.
• Works by reducing the energy needed to break
  bonds, provides easier paths for reactions.

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QUESTION

• Explain how you would use your knowledge of
  factors that affect the rate of reaction to cook
  a steak as quickly as possible.
• Temperature increase to high
• Surface Area Cut steak into pieces (increase
  area)
• Concentration none
• Cataylsts - none

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QUESTION

• What effect on the rate of reaction of a metal
  with 20 ml of dilute acid at room temperature
  would you expect if
• A) the acid was cooled to 100C?
• B) 2 ml of concentrated acid was added?
• C) the metal was ground into powder before
  addition to the acid?

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ANSWER

• A) The reaction rate would decrease (slow down)
• B) the reaction rate would increase (
  speed up)
• C) the reaction rate would increase (
  speed up )