Chemistry - electrolysis 0.0 / 5 ? ChemistryElectrolysisGCSEAQA Created by: midget17Created on: 06-04-18 14:05 Electrolysis Use of an electrical current to break down compounds containing ions into elements 1 of 14 Electrolyte Ionic compound being broken down 2 of 14 What are the electrodes made of? Inert / unreactive substances so they don't react with the electrolyte or products 3 of 14 Anode Positive electrode, negatively charged ions move to it 4 of 14 Cathode Negative electrode, positively charged ions move to it 5 of 14 What happens when ions reach electrodes? Lose charge, become elements, gases may be given off or metals were deposited 6 of 14 Oxidation when negatively charged ions lose electrons at the anode 7 of 14 Reduction when negatively charged ions gain electrons at the cathode 8 of 14 Why can ionic compounds only be electrolysed when they are dissolved in water / molten? Only then can they conduct electricity because their ions are free to move and carry their chage to the electrode. 9 of 14 Extraction of metals - requirements Metals that are more reactive than carbon can be extracted from ores, requires a lot of energy and heat, making it expensive 10 of 14 What is the role of cryolite in the extraction of aluminium? Lowers melting point of aluminium oxide, meaning less energy is needed making it less expensive 11 of 14 Electrolysis of aqueous solutions - cathode Hydrogen is produced if metal is more reactive than hydrogen, metal is produced if metal is less reactive than hydrogen 12 of 14 Electrolysis of aqueous solutions - anode Oxygen is produced unless solution contains halide ions, halogen is produced if hallide ions are present 13 of 14 Products of electrolysis of brine Chlorine gas (anode), hydrogen (cathode), sodium hydroxide solution 14 of 14
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