Chemical effects of electric current New word


electroplating – method of coating metal objects with a thin layer of another metal


An electric current can cause a chemical reaction in a solution. This chemical effect of electric current is called electrolysis. In electrolysis, chemical compounds can be broken down into simper substances. The current provides the energy for the chemical reaction. An example of electrolysis is the breakdown of water into hydrogen and oxygen gas. We can represent the reaction in the following equation:


electricity 2 molecules of water (2H2 Uses of electrolysis


Electrolysis is used to make elements such as sodium and chlorine gas. It is also used in electroplating. Objects can be plated in a thin coating of an expensive metal such as gold or silver to make them more attractive. Copper (II) chloride solution can be broken down by electrolysis into copper metal and chlorine gas. The metal forms a solid and the chlorine gas can be collected.


O) hydrogen gas (H2 ) + oxygen (O2 )


Figure 7 Electrolysis is used to electroplate cutlery and jewellery. Activity 4 Observe electrolysis of copper (II) chloride Group work


AIM Observe the effect of electric current on chemical compounds in a solution. HYPOTHESIS


Passing electric current through a solution breaks down chemical compounds.


MATERIALS • copper chloride solution (CuCl2


beaker


• two carbon rods • two insulated copper leads • two or three 1,5 V cells


) in a glass jar or


116 Topic 2 Energy transfer in electrical systems


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