P6 Rate and Extent of Chemical change

• What are the 2 equations that can be used to work out rate of reaction?

  1.)Rate of reaaction=quantity of reactants used ÷ time taken

  
  

  2.)Rate of reaction=quantity of products formed ÷ time taken
• What units is quantity measured in?

  1.)Grams/s

  2.)Cm³/s
• What is the amount of mol per minute a reaction produces if the reaction takes 2 mins and produces 0.6 mol in total?

  0.3mol as 0.6÷2=0.3
• What factors affect the rate of chemical reactions?


  1.)Temperature

  2.)Concentration or pressure

  3.)Surface area

  4.)Presence or absence of a catalyst
• What is collision theory?

  A theory that suggests for particles to react they must collide together with sufficient energy
• What is activation energy?

  The minimum amount of energy particles must have for a reaction to take place
• How does an increase in temperature increase rate of reaction?

  The particles gain more energy meaning they move faster,increasing likelihood of successful collisions
• How does an increase in concentration or pressure increase rate of reaction?

  Increases amount of particles in a volume and therefore the likelihood of successful collisions
• How does an increase in surface area increase rate of reaction?

  Increasing surface area to volume ratio increases the area on which successful collisions can take place Increasing likelihood of successful collisions
• How do Catalysts increase rate of reaction?

  They lower activation energy increasing likelihood of successful collisions due to particles more likely to have enough energy to react
• What is a catalyst?

  A substance that lowers activation energy without being used up
• Tangent=line on side

  
• What is a reversible reaction?

  A reaction that can occur forwards and backwards
• What happens in a reversible reaction if the forward reaction speeds up and the backward reaction slows down?

  There will be more products being produce than reactants
• What happens in a reversible reaction when the forward and backwards reactions are going at the same speed?


  The concentrations of the reactants and products won't change anymore
• What is the term of a reversible reaction that is balanced?

  At equilibrium
• Does a reversible reaction at equilibrium have the same amount of reactants and products?

  No
• What is the position of equilibrium of a reaction with more reactants and fewer products?

  Left
• What would the position of equilibrium of a reaction with more products and less reactants be?

  Right
• What is the condition for equilibrium to be reached?


  The reaction be in a closed system
• What is a closed system?

  A sealed environment from which none of the reactants or products can escape
• What must reversible reactions be in each direction?

  Exothermic in one direction and endothermic in the other
• What symbol do reversible reactions have in the middle?

  Double arrow
• Reversible reaction symbol

  
• What is le chatelier's principle?

  If you change the conditions of a reversible reaction the equilibrium will shift to counteract the change
• What is the Haber process?

  The industrial production of ammonia from nitrogen and hydrogen and why the reaction is done in the way it is
• What pressure and temperature are used in the Haber process?

  A temperature of 450°C and pressure of 200atm
• What catalyst is used in the Haber process?

  An iron catalyst (Fe)
• What is made from the haber process?

  Nitrogen based fertilizers
• What direction of the haber process is exothermic?

  Right direction
• What direction of the haber process is endothermic?

  Left direction
• The haber process

  
• Where does the haber process take place?

  A reaction vessel
• Why is the temperature 450°C in the Haber process?

  As the rate of reaction needs a high temperature while to get a higher percentage yield it needs a lower temp so 450°C is used to compromise
• Why is a pressure of 200atm used?

  To achieve a high percentage yield and rate of reaction a high pressure is needed however a high pressure is dangerous and expensive
• What is difficult cost wise when using a high temperature for the haber process?

  Maintenance of a high temperature is also expensive