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18. Electrolysis Of Water(Compare with Experiment 9)Material: Pill bottle -- Water & epsom salt -- 9 volt battery -- Insulated copperwire & galvanized iron nailElectrolysis is a chemical change when electricity passes through a substance.1) Liquid water is a compound made of two gases - hydrogen andoxygen. When electricity is passed through water it separates intohydrogen and oxygen and as new substances are formed it is aCHEMICAL CHANGE.2) Pure water, free from impurities, will not conduct or allowelectricity to pass through it. Pure water is a non-conductor ofelectricity.3) To make water a conductor Epsom Salt (magnesium sulfate) canbe added to it or a few drops of battery acid could be added.Note: Battery acid is corrosive and dangerous.*** Epsom salt is a safer substance to use than battery acid.

Diagram of Experiment 18●Bubbles of hydrogen gas areseen at the negativeelectrode.●●Bubbles of oxygen are seenat the positive electrode.The volume of Hydrogenproduced is twice thevolume of oxygen formed.Note: If Hydrogen is burntin oxygen - water will beformed.