C: rate/extent of chemical change: reversible reactions

• What are reversible reactions?


  Reversible reactions are chemical reactions where the products can react to produce the original reactants.
• How can the direction of a reversible reaction be changed?

  The direction of a reversible reaction can be changed by altering the conditions, such as temperature.
• What symbol is used to represent a reversible reaction?

  The symbol used to represent a reversible reaction is ⇌.
• In the Haber Process, what is the reversible reaction represented as?

  The Haber Process is represented as hydrogen + nitrogen ⇌ ammonia.
• What happens to the energy in a reversible reaction that is endothermic in one direction?

  If a reversible reaction is endothermic one way, it is exothermic in the opposite direction.
• How much energy is transferred in a reversible reaction?

  The same amount of energy is transferred each way in a reversible reaction.
• What is equilibrium in the context of reversible reactions?

  Equilibrium is reached when the reactions occur at exactly the same rate in each direction in a closed system.
• How do the relative amounts of substances at equilibrium depend on reaction conditions?

  The relative amounts of all the reacting substances at equilibrium depend on the conditions of the reaction.
• What does Le Chatelier's principle state about changes in equilibrium conditions?

  Le Chatelier's principle states that if a change is made to any of the conditions in a system at equilibrium, the system responds to counteract the change.
• What happens to the equilibrium position if the concentration of reactants is increased?

  If the concentration of reactants is increased, the position of equilibrium shifts towards products, producing more product until equilibrium is reached again.
• What occurs if the concentration of products is increased in a reversible reaction?

  If the concentration of products is increased, the position of equilibrium shifts towards reactants, producing more reactant until equilibrium is reached again.
• How does an increase in temperature affect the equilibrium of a reaction?

  If temperature is increased, equilibrium moves in the direction of the endothermic reaction.
• What happens to equilibrium if the temperature is decreased?

  If temperature is decreased, equilibrium moves in the direction of the exothermic reaction.
• What is the effect of temperature changes on the yield of a reaction?

  • For exothermic reactions:
  • An increase in temperature decreases yield.
  • A decrease in temperature increases yield.
  • For endothermic reactions:
  • An increase in temperature increases yield.
  • A decrease in temperature decreases yield.
• How does pressure affect equilibrium in gaseous reactions?

  An increase in pressure favors the reaction that produces the least number of molecules.
• What happens to equilibrium if pressure is increased in a reaction with gaseous reactants?

  If pressure is increased, equilibrium shifts to the side of the equation with fewer moles of gas.
• What occurs if pressure is decreased in a gaseous reaction?

  If pressure is decreased, equilibrium shifts to the side of the equation with more moles of gas.
• How does pressure affect the yield of a reaction?

  • An increase in pressure:
  • Decreases yield if the reaction produces a larger volume of gas.
  • Increases yield if the reaction produces a smaller volume of gas.
  • A decrease in pressure:
  • Increases yield if the reaction produces a larger volume of gas.
  • Decreases yield if the reaction produces a smaller volume of gas.