c8 rates of reactions

• the rate of reaction tells you how fast a reaction is going
• we can find the rate of reaction by timing

  • how quickly products are made
  • how quickly reactants are used
• as time goes on the rate of reaction decreases because the products are being used up so there are less frequent collisions
• how to speed up a reaction

  • increase temperature
  • increase concentration/pressure
  • increase SA:V
  • add a catalyst
• increase temperature

  • particles have more energy
  • more frequent collisions
  • increased rate of reaction
• increased concentration/pressure

  • more particles in a given volume
  • more frequent collisions
  • increased rate of reaction
• increase SA:V

  • more particles exposed
  • more frequent collisions
  • increased rate of reaction
• the steeper the gradient the faster the rate of reaction
• graphs curve because

  • reactants get used up
  • fewer collisions
  • rate slows down
  • reaction stops when reactants are used up
• increasing the rate of reaction only speeds up the time it takes to make the amount of products and not how much is made
• most chemical reactions only go in one direction
• reversible reactions can go in both directions
• in reversible reactions, one direction is exothermic and the other is endothermic
• if a reversible reaction takes place in a closed system an equilibrium is set up
• equilibrium occurs when the rate of the forward reaction is equal to the rate of the bacward reaction
• in equilibrium the amount off reactants and products reach a balance
• equilibrium can only occur in a closed system
• changing the conditions of a reaction at equilibrium causes the position of equilibrium to shift in the direction that counters the change
• concentration change at equilibrium

  • an increase in concentration of reactants causes the equilibrium to shift towards the products
  • increase in concentration of products causes the equilibrium to shift towards the reactants
• temperature change at equilibrium

  • increase in temperature causes equilibrium to shift in endothermic direction
  • decrease in temperature causes equilibrium to shift in exothermic direction
• pressure change at equilibrium

  • increase pressure causes equilibrium to shift to the side with fewer moles
  • decrease in pressure causes equilibrium to shift to the side with more moles
• equilibrium yield


  how much is made of the products