Lab Module 1- Rates of Reactions using different Catalyst.
Objective: The students will use different chemical compounds to determine the best catalyst
for the production of carbon dioxide from the reaction of hydrogen peroxide and potassium
hydrogen tartrate (cream of tartar).
Information
Iron act as a catalyst but the iron has to be in the ionic state. Solid stable iron is not adequate..
As hydrogen peroxide oxidizes potassium hydrogen tartrate (cream of tartar), CO 2 is produced
in an easily observable exothermic reaction. All of the reagents for this demonstration are
obtained from household products. The iron ions are produced by boiling steel wool in vinegar
to create a mixture of ferrous acetate and ferric acetate. The acetic acid also makes the solution
more acidic, which is required for the optimal performance of Fenton's reagent. The steel wool
is first cleaned with nail polish remover containing ethyl acetate to remove grease. The
potassium hydrogen tartrate is simply household cream of tartar used in baking, and the
hydrogen peroxide is the 3% solution commonly sold in drug stores and grocery stores.
Materials
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iron acetate solution (clean steel wool with acetone(fingernail polish) and then
heat 15 ml/per group of vinegar and soak steel wool in it for 15 minutes to create
iron acetate solution)
150 mL 3% hydrogen peroxide
3 g cream of tartar
Acetone
Steel wool
vinegar
Stir rod
Temperature probe/thermometer
Prerequisite Laboratory Skills: basic lab skills
Procedure
1. To perform the experiment, add 50 mL of 3% H2O2 to 3 200mL beakers followed by 1g
cream of tartar in each one. Stir and take the temperature of each beaker.
2. Add a small amount of cleaned steel wool to the first beaker. Stir and monitor the
temperature-taking temperature readings every two minutes.
3. Add 5 ml of vinegar to beaker #2. Stir and monitor the temperature-taking temperature
readings every two minutes.
4. Add 5 mL of the iron acetate solution to beaker #3. Stir the solution until bubbles begin
to form on the surface, the reaction should proceed with more bubbles forming as CO 2
is evolved. Be cautious as the beaker becomes very hot. Take temperature readings
every 2 minutes.
5. Continue taking temperature readings for the three beakers and record the
temperatures for 20 minutes. You should had 10 temperature readings per beaker.
Data Using the graph paper supplied by your teacher-graph the temperature vs time lines for all three
beakers. Note the difference in Beakers 1 & 2 compared to Beaker 3.
Conclusion: iron in the form of steel wool is iron metal and not in the form of a free flowing ion. When
soaked in vinegar, iron reacts with the acetate and forms the ionic compound iron acetate (both ferrous
and ferric acetate are formed). This iron ion is able to be a catalyst for the reaction of hydrogen
peroxide and cream of tartar. Without the iron ionic particles, the reaction doesn’t take place.
Data Table.
Time
2 min
4 min
6 min
8 min
10 min
12 min
14 min
16 min
18 min
20 min
Extensions:
Beaker 1-Temperature
Beaker 2- Temperature
Beaker 3- Temperature
Use different time, temperature and agitation when making the iron ions to try to create smaller iron
ions that would give greater surface area for the catalyst reaction to occur. Vary the formation of iron
acetate by making it very slowly by soaking it overnight, agitating it as it reacts, and boiling the solution.
If possible, use an electron scanning microscope to determine the size of the catalyst formed.