reversible reactions

• What are reversible reactions?

  Reactions that can proceed in both directions
• What does the term equilibrium refer to in reversible reactions?

  when the for ward and backward reaction occurs at the same rate
• What does a single arrow in a chemical reaction indicate?

  It indicates a one-way reaction
• What does a double arrow in a chemical reaction signify?

  It signifies a reversible reaction
• How do the rates of forward and backward reactions change over time?

  The forward reaction slows down while the backward speeds up
• What happens when the forward and backward reactions reach the same rate

  The reaction is at equilibrium
• What does it mean when a reaction is at equilibrium?

  Both reactions are happening but cancel each other out
• Can the concentrations of reactants and products be the same at equilibrium?

  No, they can be different but constant
• What does it mean if the equilibrium lies to the right?

  There are more products than reactants
• What does it mean if the equilibrium lies to the left?

  There are more reactants than products
• How can the position of equilibrium change?

  By altering the conditions of the reaction
• What effect does adding heat have on the position of equilibrium?

  It encourages the forward reaction
• What happens to the position of equilibrium when the reaction is cooled?

  It shifts back to the left
• What is required for equilibrium to be reached in a reversible reaction?

  A closed system where reactants and products cannot escape
• Why are reversible reactions always exothermic in one direction?

  One direction releases heat while the other absorbs
• What does hydrated mean?

  Water is present
• What does anhydrous mean?

  No water is present
• What happens when hydrated copper sulfate is heated?

  It drives the reaction to form anhydrous copper sulfate
• What occurs when heat is removed from anhydrous copper sulfate and water is added?

  It drives the backward reaction to reform blue crystals
• What are the key points about reversible reactions and equilibrium?

  • Reversible reactions have a double arrow
  • Equilibrium is when reactants and products' concentrations are constant
  • Position of equilibrium can shift left or right
  • Forward reaction is endothermic; backward is exothermic
  • Equilibrium requires a closed system
• what does increasing the temperature favour

  the endothermic reaction
• what does decreasing the reaction favour

  exothermic reaction
• what does increasing the pressure favour

  the side of the reaction with the fewer moles of gas
• what does decreasing the pressure favour

  the side of the reaction with more moles of gas