Rate and Extent of Reaction

• Reaction Rate


  Change in concentration of reactants or products PER UNIT TIME.
• Catalyst 


  A substance that increases the rate of chemical reaction without itself undergoing a permanent change.
• What does a catalyst do?

  Lowers the activation energy
• 3 Fundamentals of Collision Theory


  1. Molecules must collide.

  2. Molecules must have the correct orientation.

  3. Must have enough Activation Energy.
• 5 ways to change/influence collisions 


  1. Surface Area (solids)

  2. Concentration (Liquids)

  3. Pressure (gases)

  4. Temperature

  5. Catalyst
• Collision Theory Surface area (Solids) 


  • Increasing the surface area
  • increases the number of particles able to react, thus increasing the reaction rate, thus MORE EFFECTIVE COLLISIONS PER UNIT TIME.
• Collision Theory Concentration (Liquid) 


  • The rate of reaction increases when the concentration of reactants in solution is increased, thus MORE EFFECTIVE COLLISIONS PER UNIT TIME.
• Collision Theory Pressure (Gases) 


  • An increase in the pressure of a gas (smaller area/container) increases the rate of reaction, Thus MORE EFFECTIVE COLLISIONS PER UNIT TIME.
• Collision Theory TEMPERATURE! 


  • A change in temperature can increase or decrease the rate of reaction. -
  • An increase in temperature increases the speed of particles, and thus they collide more often. Also gives them more energy, meaning that more particles will now meet the activation energy, thus MORE EFFECTIVE COLLISIONS PER UNIT TIME.
• Collision Theory Catalyst

  • Substance that increases the rate of chemical reaction whilst not undergoing permanent change itself.
  • lowers the activation energy of the reaction, thus MORE particles will react, thus MORE EFFECTIVE COLLISIONS PER UNIT TIME.

  
  

  2 Types:

  1.) Homogeneous Catalyst:

  • The catalyst and reactants are in the same phase.

  2.) Heterogeneous Catalyst:

  • The catalyst and reactants are in different phases.
• 2 Ways to Measure Rate/Speed of Reaction

  
  

  • Measure the volume of gas collected.
  • Measure the mass of the flask.
• 3 changes that can be made to the Maxwell-Bolstman Distribution Curve.

  1.) Concentration

  • Increases the number of particles able to react.
  • making the graph larger/higher

  2.) Temperature

  • Increases: ---> Shifts graph right
  • Decreases ---> Shifts graph left

  3.) Catalyst

  • Doesn't change the graph
  • Decreases activation energy
• Activation Energy 


  Minimum energy needed by the particle for the reaction to take place.