Presentation on theme: "Electrochemistry making elements using electricity"— Presentation transcript:
1Electrochemistry making elements using electricity Chemistry C2 Part FiveRevision PowerPoint - Big ideasElectrochemistry making elements using electricity
2Electrolysis and ionic compounds In electrolysis an electric current is passed through an ionic compound, either molten or in solution.The compound breaks down into elements.
3LEO the LION says GERrrr Oxidation happens at the positive electrode. Negative ions lose electrons.Reduction happens at the negative electrode. Positive ions gain electrons.OXIDATION AND REDUCTIONLEO the lion says GERLosing Electrons is Oxidation,Gaining Electrons is Reduction.
4Electrolysis in action The experiment uses a direct currentThe electrodes allow electrons to enter or leave the solutionThe electrolyte is the ionic compound
5ElectroplatingMetal objects are electroplated by making them the negative electrode and placing them in a solution of soluble ions. e.g. nickel plating copper
6Extracting aluminiumAluminium is extracted by electrolysis of molten bauxite dissolved in cryolite.
7Brine and the chlor-alkali industry The electrolysis of brine (salt water) produces sodium hydroxide, chlorine and hydrogen.Sodium hydroxide is used to manufacturesoaps and detergentsrayon and acetate fibrespaperceramicsChlorine is used to manufactureantiseptics and disinfectantspesticides and weed-killersbleachand to kill bacteria in drinking waterHydrogen is used to manufacturemargarineammoniaIt is used in fuel cells and in rocket fuels for space craft
8Electrolysis of brineChloride ions are discharged as chlorine gas at the +ve electrode. Hydrogen ions are discharged at the –ve electrode as hydrogen gas. Sodium and hydroxide ions are left as sodium hydroxide solution.