Week 3

• Chemical equilibrium


  State reached by a reaction mixture when the rates of forward and reverse have become equal
• Reversible reactions


  1. Reaction occurs in either direction

  2. All ionic reactions may be considered to be reversible to some degree

  3. Any chemical reaction once initiated maybe regarded as being the result of two opposing reactions
• Reaction velocity


  The change in concentration in unit time
• Reaction kinetics


  The study of rates of chemical reactions and the factors which influence reaction velocities
• Factors affecting rate of reaction

  • Nature of reactants
  • Presence of catalysts
  • Temperature
  • Concentration
• Nature of reactants


  • Determines the amount of activation energy that should be present for a reaction to occur
  • Refers to the physical state of the reacting substances
• Catalysts


  Substances that increase or decrease the rate of chemical reaction without being consumed or transformed
• Types of catalysts

  • Positive (accelerates or increases the reaction rate through lowering of activation energy)
  • Negative (retards or slows down the reaction rate)

  
• Temperature


  A measure of the average kinetic energy of the molecule
• Increase in temperature

  Increases the rate of reaction
• Concentration


  The amount of substance per unit volume