Collision Theory

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Collision Theory
Chemical Kinetics
Factors Affecting Reaction Rate

• In order for a reaction to occur, reactant
  particles must collide with each other.
• In order for a reaction to occur, the collisions
  must be effective.
• Effective collisions sufficient energy and
  correct orientation.

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H2 I2 ? 2HI
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Factors Affecting Rate of Reaction

• 1. Nature of Reactants
• 2. Surface Area
• 3. Temperature
• 4. Concentration
• 5. Pressure
• 6. Catalyst

Increasing frequency of effective collisions
increases rate of reaction.
http//glencoe.com/sec/science/cgi-bin/splitwindow
.cgi?tophttp//www.glencoe.com/sec/science/top2.h
tmllinkhttp//www.educationusingpowerpoint.org.u
k/Animations/rates20of20reaction.html
http//phet.colorado.edu/new/simulations/sims.php?
simReactions_and_Rates
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1. Nature of Reactants

• _____________________________ bonded substances
  are slower to react than _________________________
  _____ bonded substances.

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How does increasing surface area affect reaction
rate?
Mg(s) 2HCl(aq) ? MgCl2(aq) H2(g)
Large Piece of Mg
Small Pieces of Mg
http//www.crocodile-clips.com/absorb/AC4/sample/L
R1502.html
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2. Surface Area

• Draw a curve (graph) showing the relationship
  between surface area and reaction rate
• Relate this relationship to collision theory

As surface area increases, reaction rate
________________.
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3. Temperature

• Draw a curve (graph) showing the relationship
  between temperature and reaction rate
• Relate this relationship to collision theory

As temperature increases, reaction rate
__________________.
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Concentration
HC2H3O2 NaHCO3 ? NaC2H3O2
H2CO3 Acetic Sodium Sodium Carbonic
Acid Bicarbonate Acetate Acid
H2CO3 ? H2O CO2 Carbonic
Water Carbon Acid
Dioxide
http//www.crocodile-clips.com/absorb/AC4/sample/L
R1503.html
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4. Concentration

• Draw a curve (graph) showing the relationship
  between concentration and reaction rate
• Relate this relationship to collision theory

As concentration increases, reaction rate
________________.
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5. Pressure

• Draw a curve (graph) showing the relationship
  between pressure and reaction rate
• Relate this relationship to collision theory

As pressure increases, reaction rate
________________.
http//www.crocodile-clips.com/absorb/AC4/sample/L
R1503.html
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6. Catalyst

• Catalyst The addition of a catalyst ___________
  reaction rate.

Definition of a catalyst
http//www.eepybird.com/dcm1.html
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Homework

• Collision Theory
• Orange Book Pg. 110, Q 1-10
• Pg. 121, Q 1, 2, 4, 5
• Pg. 123, Q 18, 19,
  21, 22, 23
• Must do. Other HW questions are optional.