Rates of reaction

• What is the collision theory?

  The collision theory states that chemical reactions occur when particles collide with sufficient energy.
• What is the activation energy?

  The minimum energy required for a chemical reaction to occur.
• what does a catalyst do?

  Speeds up a chemical reaction without it being used up.
• what FACTORS affect the rate of reaction?


  • Temperature
  • concentration
  • surface area
  • catalysts.
• How does temperature affect the rate of reaction? 


  Increase temp$\Rightarrow increases\ KE\ of\ particles$

  = MORE FREQUENT COLLISION
• how does concentration affect the rate of reaction?

  Increase$\rightarrow Increases\ number\ of\ particles\ in\ GIVEN\ VOLUME$

  =faster reaction and frequent collisions
• how does surface area affect the rate of reaction?

  Increase= faster reaction

  As it increases frequency of collisions
• collision theory


  • reactant particles must collide with enough energy to produce reaction
• Practical on effect on conc

  10 cm sodium thiosulphate solution

  Place flask on black cross

  Add 10cm hydrochloric acid

  Swirl and stopwatch

  Stop when cloudy

  Repeat with lower conc of sodiu

  Repeat and calculate mean
• Volume of gas produced practical

  50 centimetres hydrochloric acid into flask and connect to bong and delivery tube

  Place delivery tube into container with water

  place upturned measuring cylinder filled with water over delivery tube Three centimetres strip of magnesium into hydrochloric acid and start stopwatch

  Measure volume of hydrogen gas every 10 seconds and repeat using different concentrations of hydrochloric acid
• Reactants higher than products

  exothermic
• Products higher than reactants

  Endothermic