MOI UNIVERSITY
SCHOOL OF ENGINEERING
CHEMICAL & PROCESS ENGINEERING LABS
TEC 112 CHEMISTRY FOR ENGINEERS
CHEMICAL REACTION KINETICS
DETERMINATION OF THE ENERGY OF ACTIVATION OF A REACTION
THEORY
Chemical kinetics concerns itself with rates of reaction measurements proceeding under given conditions of
temperature, pressure, concentration etc. The rate of a reaction is the rate of change of amount or concentration of
a particular reactant or product with time. Rates of reaction may be measured in various ways. One such method
is titrimetric in which the reaction mixture is usually quenched and then titrated against a known standard to
determine the concentration of the product or reactant. In this experiment the rate of the reaction at various
temperatures of permanganate (magnet (VII), ions with oxalate ions is investigated. This is done by finding the
time taken for the purple color to disappear after mixing solutions of these ions. Any brown suspension is
disregarded. The oxalic acid solution of concentration 0.05 M is made up in 1 M solution of sulphuric acid.
PROCEDURE
1. Measure 5ml of 0.02 M potassium permanganate (𝐾𝑀𝑛𝑂4 ), and 5ml of the oxalic acid into separate
boiling tubes.
2. Put the boiling tubes into a 250 ml beaker containing water and heat to about 320 K (470C)
3. Remove the burner from under the tripod and allow the temperature to become steady before pouring one
solution into the other and immediately start the stop watch.
4. Stir the solution with glass rod and record the time (in seconds), for the purple colour to disappear (the
average of the temperature at the start and the finish of the reaction is taken as the temperature of the
reaction.)
5. Repeat the procedure (1- 4) several times stopping the heating of the beaker at 330 K (57 0C), 340 K
(670C), 350 K (770C), 360 K (870C), 370 K (970C).
6. Plot the graph of the time (t), of the reaction (vertical axis), against the temperature (00- 1000) (horizontal
axis).
7. Also plot a graph of log to base ten of time (vertical axis) versus the reciprocal of the thermodynamic
temperature (horizontal axis) and draw your conclusions.
8. What is the effect of raising the temperature from 340 K to 350 K on the rate of the reaction?
9. What is the activation energy of a chemical reaction?
10. How do you calculate activation energy?
11. What is the unit of activation energy?
12. Can you have a negative activation energy?
13. Write equation of the reaction and draw your conclusions.
CHEMICAL & PROCESS ENGINEERING MOI UNIVERSITY