Rates of reaction

• How do you calculate rates o reaction ?

  reactants used/time = solid dissolving g/s

  products formed/time=solid forming cm3/s
• What factors affect rate of reaction

  concentration(lq)

  -catalyst

  -surface area(s)

  -pressure (g)

  -temperature
• Explain how temperature affects ror?

  increasing temp increases the freq of collisons and makes the collisions more energetic so increase rates of reaction
• Explain how concentration affect the ror?

  increasing the conc,increases the freq of collisons as there are more particles in a given volume,so rate of reaction increases
• Explain how pressure affects ror?

  increasing pressure of reacting gases means reducing the area/volume so freq of collisons increases so rate of reaction increases]
• Explain how surface area affects ror?

  increasing s.a exposes more particles so the freq of collisons increases so rate of reaction increases
• Explain how catalysts affects ror?

  by providing an alternative pathway with a lower activation energy

  (catalysts are added/they are not ysed up)

  ror increases
• Explaing the Sodium thiosulfate and hydrochloric acid practical-cross disappering


  -Measure 20cm3 of sodium thiosulfate added it to the conical flask

  -place flask on x

  -add 10cm3 of HCL and start timer

  -time until the x disappears and stop timer

  -repeat with different conc of sodium thiosulfate

  IV-conc and sodium

  CV-conc and HCL

  DV-time taken
• Explain the calcium carbonate and hydochloric acid practical-collecting of gas

  -measure 20cm3 of HCL and pour into a concial flask

  -set up a gas syringe

  -measure 2g of CACO3 (large chunks),add to conical flask,start timer

  -meaure the volume of gas collected every 30s until no gas produced

  -repeat with different s.a of CACO3

  IV-s.a of CACO3

  DV-volume of gas produced

  CV-volume and conc,HCL, mass of CACO3
• What is a reverisble reaction

  reaction that can go backwards and forwards
• define equilibriums

  when the rate of forward and reverse reaction are equal in a closed system
• state le chateliers principle

  when a system in equlibrium is subjected to a change the position of the equilibrium will shift to minimise the change
• how does the concentration change the conditions on equilibrium

  if the conc of reactants increases the system will not be equal so it will shift to produce more products

  if the conc of products increases the system will shift to produc more reactants
• how does pressure affects the changing conditions of the equilibrium

  increase in pressure causes the system to shift to the side with fewer moles of gas

  decrease in pressure causes the system to shift to the side with more moles of gas
• -increase the concentration of reactants will shift of the side of the products

  -increase the concentration of products will shift to the side of reactants
• -decrease the concentration of the reactants will shift to the reactants

  -decrease the concentration of the products will shift to the products