Science Lab Experiment: Electrolysis
Demonstration: Electrolysis
Object: To separate water into its elements.
Materials: sulfuric acid (H2SO4), Hoffman apparatus, 9-volt battery, stand and clamp, test tube,
wooden splint
Diagram:
Method: The materials were set up as shown in the diagram. Some sulfuric acid was mixed with
the water to improve the condition of electricity. The Hoffman apparatus was connected
to a 9-volt battery.
Observations: Bubbles were observed in the two outer tubes of the apparatus when the battery
was connected. After a half hour the volumes of the gasses in the outer tubes
were compared and tested. The volume in the tube connected to the negative
terminal of the battery was found to be twice the volume of the gas in the tube
connected to the positive terminal of the battery. When tested with a burning
splint the gas with twice as much volume "popped", showing that it was hydrogen.
The other gas burned, proving it was oxygen.
Conclusions: Electricity will separate water into hydrogen and oxygen. Hydrogen, as a
positively charged element, is attracted to the negative electrode. Oxygen, as a negatively
charged element, is attracted to the positive electrode.
