Rate of Reaction

Purpose:

You will be determining the effect of temperature and concentration on the rate of reaction. You must determine higher and lower molarities for 50 ml of solution.

Materials:

1. watch
2. graph paper
3. testubes
4. testube rack
5. thermometer
6. small graduated cylinder
7. eyedropper

Chemicals:

• 1 drop of 0.02 M potassium permanganate to be added to 5 ml of 5.0 M oxalic acid OR 5 ml of 0.1 M potassium persulfate with 10 drops of starch solution added to 5 ml of 0.2 M potassium iodide.

Procedure:

1. Note the color os the chemicals before mixing.
2. Combine the chemicals and start timing.
3. When the pink color turns yellow for potassium permanganate OR green-yellow for potassium persulfate stop timing and record the elapsed time. For timing it may be easier to check by holding the testube with the chemicals in front of a newspaper until the words disappear.
4. Take the temperature of the solution.
5. If the reaction was too slow do the same experiment over using solutions at least 10^oC higher.
6. If the reaction was rapid, percool the solutions 10^oC and do it again.
7. Repeat a third time using another temperature.

8. Next you will find out the affect of concentration upon the reaction.
9. Be sure to run the reaction at the same temperature as one you have done before and change the concentration of only one reactant.

Data: Make up two data tables and two graphs to show the results of your experiments.

Conclusion: Relate this experiment to what is expected for temperature and concentration effects.

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