rate of reaction

• measuring volume of gas produced at fixed intervals

  1. set up the experiment as shown in the diagram
  2. start the stop watch once the magnesium ribbon is allowed to react with the hydrochloric acid
  3. record the volume of hydrogen produced in the gas syringe at fixed intervals (e.g. every 0.5min)
  4. stop the experiment once the volume of gas produced remains constant as it indicates that reaction is complete
  5. use the results obtained to plot a graph of the volume of gas produced against time
• Experiment setup

  1. Set up the experiment as shown in the diagram

  2. Cotton wool is plugged at the mouth of the conical flask to prevent acid spray from splashing out

  3. Pull the string to allow calcium carbonate to react with hydrochloric acid

  4. Start the stop watch

  5. Record the mass at regular intervals of time until the balance reading remains constant which indicates that reaction is complete
• Loss in mass at fixed interval time
• Record the mass of the conical flask and its contents
• Use the results obtained to plot a graph of the mass of the conical flask and its contents against time
• Mass of the flask and its contents decrease as carbon dioxide gas escapes from the flask during the reaction
• as the concentration of the solution increases, the gradient of the curve becomes steeper. reaction ends faster as it takes a shorter time to complete
• when concentration of reactant increases, volume of gas produced is the same as the limiting reactant limits the amount of gas produced
• when catalyst is used, rate of reaction increases but the volume of gas remains the same

  catalyst does not affect the quantity of product formed

  catalyst affects the amount of product formed per unit time
• from monobasic to dibasic, the gradient of the curve becomes steeper