Paper 3: Required practical 7 - Measuring rate of reaction

Question 1

What is the initial rates method?

Answer 1

Measuring the initial rate of reaction for multiple different concentrations to observe how rate of reaction varies

Question 2

What are the issues with the iodine clock reaction?

Answer 2

• Some low I- concentrations may take too long to react
• Deleayed stopwatch reactions
• Concentrations may not be exact due to measuring apparatus

Question 3

What is a continuous monitoring method?

Answer 3

This involves measuring the change in concentration of a reactant or product over time as the reaction progresses

Question 4

How would you analyse the data from a continuous montioring experiment?

Answer 4

• Plot a graph of volume of hydrogen gas produced (y) against time for each concentration of HCl - draw a lob
• Draw a tangent at t=0s for each line
• Calc gradient of each tangent
• Compare the calculated rate values

Question 5

What are some issues with this experiment?

Answer 5

• Some gas may escape before the bung is added
• Mg strips may be of different mass and surface area

Question 6

How do you prevent gas escaping?

Answer 6

Place the solid reactant upright inside a sample tube in the conical flask, tipping the tube over by moving the conical flask around to start the reaction