Extracting metals and equilibria

• Reversible reactions

  The products can react to reform the reactants

  
• Energy changes reversible reactions

  Energy changes are equal and opposite
• If the forward reaction is endothermic

  The reverse reaction is exothermic
• If the forward reaction is exothermic

  The reverse reaction is endothermic
• Anhydrous

  Describes a substance that does not contain water
• Reversible reaction of copper sulfate

  CuSO4 + 5H2O --> CuSO4.5H2O

  
• Dynamic equilibrium

  When the rate of the forward reaction is the same as the rate of the reverse reaction

  
• Closed system

  A system in which no matter is allowed to enter or leave
• Matter

  Anything that has mass and takes up space
• Le Chatelier's Principle

  If a reaction at equilibrium is disturbed the equilibrium position will move to counteract the disturbance.
• Equilibrium position

  The relative amounts of reactants and products of at equilibrium
• Equilibrium shifts right

  Equilibrium moves to make more products
• Equilibrium shifts left

  Equilibrium moves to make more reactants
• Effect of increasing temperature on equilibrium

  Moves equilibrium position toward endothermic reaction
• Effect of decreasing temperature on equilibrium

  moves equilibrium position toward exothermic reaction
• Effect of increasing pressure on equilibrium

  moves equilibrium position in the direction of the reaction which produces fewest moles of gas
• Effect of decreasing the pressure on equilibrium

  moves equilibrium position in the direction of the reaction which produces most moles of gas
• Effect of catalyst on equilibrium

  Speeds forward and reaction equally, equilibrium position does not change, equilibrium is reached more quickly
• Effect of decreasing substance concentration on equilibrium

  Equilibrium position moves to replenish concentration
• Effect of increasing substance concentration on equilibrium

  Equilibrium position moves to reduce substance concentration
• The haber process

  An industrial process for producing ammonia
• Ammonia

  NH3
• Haber process catalyst

  Iron
• Reactants in Haber process

  N2 + H2
• N2 + 3H2 ⇌

  2NH3
• Conditions for Haber process

  450 degrees, 200 atm, iron catalyst, recycle unreacted gases back through the reactor