RP 03 Effect of Temp. on ROR

• How can rate of reaction be measured?

  • Initial rates method - iodine clock reaction
  • A continuous monitoring method - measuring the volume of gas released in a reaction over time
• Why does the rate of reaction increase with increasing temperature?

  • Increase in temp. = increase in ke of molecules - more molecules have energy greater than activation energy therefore they react
  • Also as ke of molecules increase, velocities increase which induces more frequent+successful collisions
• How would you investigate how rate of reaction varies with temperature?

  • Time how long it takes for a cross underneath the beaker to disappear, using a stopwatch
  • Repeat this at 5+ different temperatures and compare times taken
• What are some issues with this method?

  • The disappeared cross is judged by eye and therefore it can be unreliable
  • There may be a delayed reaction time with the stopwatch
  • At low temperatures the reaction may be too slow
  • There may not be enough precipitate for the cross to disappear
• In an experiment investigating the effect of temperature on rate of reaction, what variables would you control?

  • concentrations of reactants and products
  • volumes of reactants and products
  • use the same beaker and cross underneath
  • use the same person to decide when the cross has disappeared
• How can we keep a substance at a constant temperature?

  Using a water bath keeps the temperature constant. For this experiment you can set up water baths of different temperatures to see how it affects rate of reaction.