CHEMICAL EQUILIBRIA

• Closed System

  A system in which no reactants or products are able to escape
• Dynamic Equilibrium

  A reversible reaction where the forwards and backwards reactions happen at the same time and at the same rate so there is no net change in products and reactants
• Le Chatelier’s Principle

  If the conditions of a reaction at equilibrium are changed, then the position of the equilibrium moves to oppose that change.
• What is the effect of a catalyst on an equilibrium?

  It speeds up the rate of both the forward and backwards reactions equally, so it does not change the position of the equilibrium.
• What happens if the temperature is increased?

  equilibrium favours the endothermic reaction
• What happens if the temperature is decreased?

  equilibrium favours the exothermic reaction
• When does pressure apply to an equilibrium?

  when there is gas
• What happens if pressure is increased?

  equilibrium shifts to less moles of gas
• What happens if pressure is decreased?

  equilibrium shifts to more moles of gas
• What happens if the concentration of a substance has increased?

  equilibrium shifts to use it up
• What happens if the concentration of a substance decreases?

  equilibrium shifts to form more
• What is the equation for the equilibrium constant, Kc?

  Kc = [products] / [reactants]
• What do we use to calculate the concentrations of the reactants and products?

  moles at equilibrium
• What is the only thing that changes the equilibrium constant?

  Temperature
• What happens to the equilibrium constant if less product is produced?

  Decreases
• What do the square brackets stand for?

  Concentration