Powerpoint

• Dynamic equilibrium


  Equilibrium in terms of concentrations and rate
• Equilibrium Constant


  1. Write

  2. Calculate

  3. Manipulate
• Le Chatelier's Principle


  • Changes in concentration, pressure, or temperature can disturb the equilibrium and lead to a shift in the equilibrium position
• Position of equilibrium


  The relative amounts of reactants and products present at equilibrium
• Equilibrium doesn't mean that there are 50% reactants and 50% products
• Equilibrium shift to the right


  Favors the forward reaction, more products are made
• Equilibrium shift to the left


  Favors the backward reaction, more reactants are made
• Changes that affect equilibrium

  1. Changes to the concentrations of reactants and products

  2. Changes to the pressure of a system involving gaseous reactants and products

  3. Changes to the temperature
• Videos on Le Chatelier's Principle


  • https://youtu.be/7zuUV455zFs
  • https://youtu.be/XhQ02egUs5Y
• If hydrogen is added

  Equilibrium will shift to the right, concentrations of hydrogen and nitrogen decrease, concentration of ammonia increases
• If ammonia is removed

  More nitrogen and hydrogen will react to replace the ammonia, equilibrium position will shift to the right
• Increasing concentration


  Sends the equilibrium towards the opposite side
• Decreasing concentration


  Sends the equilibrium towards the same side
• If pressure is increased


  Equilibrium position will shift to the side with the lowest number of gaseous molecules
• If pressure is decreased


  Equilibrium position will shift to the side with the greatest number of gaseous molecules
• For reactions with the same number of gaseous molecules on each side, changes in pressure will have no effect on the equilibrium position
• Increasing pressure


  Sends the equilibrium towards the side with less molecules
• Decreasing pressure


  Sends the equilibrium towards the side with more molecules
• If temperature is increased

  Equilibrium position will shift in the endothermic direction
• If temperature is decreased


  Equilibrium position will shift in the exothermic direction
• The enthalpy value quoted beside the equation for a reversible reaction refers to the value for the forward reaction
• If the forward reaction is endothermic, the reverse reaction will be exothermic and vice versa
• Increasing temperature


  Makes the reaction go in the endothermic direction
• Decreasing temperature


  Makes the reaction go in the exothermic direction
• A catalyst increases the rate of a chemical reaction by providing an alternative reaction pathway with a lower activation energy
• The presence of a catalyst has no effect on the equilibrium position because it increases the rate of both the forward and reverse reactions by the same amount
• The advantage of using a catalyst is that the equilibrium is established more quickly, which is an economic benefit