rate of reaction practicals

• What is the independent variable in the gas production experiment?

  Surface area of marble chips
• How does changing the surface area affect the rate of reaction?

  It alters the amount of gas produced
• What should be done with the measuring cylinder before starting the experiment?

  Fill it with water
• What is the dependent variable in the gas production experiment?

  Volume of gas produced
• What is the purpose of starting the timer in the experiment?

  To measure the time for gas production
• How often should the volume of gas produced be recorded?

  Every 5 seconds
• What should be plotted on the graph after recording data?

  Time against volume of gas
• What is the next step after plotting the graph?

  Draw a curve of best fit
• How can the rate of reaction be determined from the graph?

  By calculating the gradient
• What is the procedure for measuring gas production in the reaction?

  1. Set up equipment with a full measuring cylinder.
  2. Place a known mass of marble chips.
  3. Pour in a known concentration and excess volume of acid.
  4. Start the timer.
  5. Record gas volume every 5 seconds.
  6. Plot time against gas volume.
  7. Draw a curve of best fit.
  8. Calculate the gradient for rate.
• What reaction is observed to study the rate of reaction?

  Reaction between sodium thiosulfate and hydrochloric acid
• How does changing concentration affect the rate of reaction?

  It affects the rate by changing the colour
• What is the procedure for observing a colour change in this experiment?

  1. Set up equipment with an 'x' visible.
  2. Place solutions (except acid) in beakers.
  3. Pour in acid (independent variable) and start the stop clock.
  4. Stop the clock when the cross is not visible (dependent variable).
  5. Repeat with different acid concentrations.
  6. Plot a graph of time against acid concentration.
  7. Draw a line of best fit.
  8. Calculate the gradient for rate changes.
• What is the independent variable in this experiment?

  Concentration of hydrochloric acid
• What is the dependent variable in this experiment?

  Time taken for the cross to disappear
• What should be done after repeating the experiment with different concentrations?

  Plot a graph of time against concentration
• What does calculating the gradient of the graph indicate?

  How the rate changes per increase in concentration
• What should be visible under the reaction vessel during the experiment?

  An 'x' on a sheet of paper
• What is the first step in the experimental setup?

  Set up equipment with an 'x' visible
• Why is it important to repeat the experiment with different concentrations?

  To observe how concentration affects the rate
• What is the significance of drawing a line of best fit on the graph?

  It helps visualize the relationship between variables