The genie of the lamp
Objective: The goal of this experiment is to release a white smoke from a flask simulating the appearance of a genie
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Laboratory material
500 mL volumetric flask
Filter paper
50 mL measuring cylinder
Funnel
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Chemicals
Hydrogen peroxide (H2O2) al 30%
Manganese dioxide (MnO2)
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Safety
Do not forget the lab coat, the gloves and the safety glasses!!!
Perform the experiment inside the fume food and discard the remains in the “metals” waste.
Watch out! The volumetric flask gets very hot after the reaction. Wait until it cools down before touching it.
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Protocol
Weight 0.3 g of manganese dioxide and wrap them in a filter paper.
Measure 50 mL of 30% hydrogen peroxide in the cylinder and pour them inside the volumetric flask using the funnel.
Finally, add the filter paper containing the manganese dioxide all at once and step back.
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Questions
Which reaction takes place? Write it down.
Is the smoke dangerous?
Why is the flask getting hot?
Has the manganese dioxide reacted? Where is it after the reaction?
Theoretical explanation
In this experiment, the manganese oxide acts as a catalyst and its role is to increase the speed at which the hydrogen peroxide decomposes into water and oxygen. This is an exothermic reaction, meaning it releases heat. As a result, the oxygen and water formed come out in the form of steam, simulating the effect of the appearance of a genie.
The decomposition reaction of hydrogen peroxide catalyzed by manganese oxide is represented as follows:
2 H2O2 2 H2O + O2
It is interesting to note that, despite accelerating the reaction, the catalyst is not consumed during the process. This is why a small amount of MnO2 can decompose a large amount of hydrogen peroxide. In fact, if we look carefully inside the flask once the reaction has finished, we will be able to see the manganese oxide (black powder).
