C2 Chapter 5 Electrolysis 4.0 / 5 based on 1 rating ? ChemistryElectrolysisGCSEAQA Created by: ColdAsteroidCreated on: 01-01-16 10:22 What are ionic compounds? Compounds that contain ions (charged ions) 1 of 31 What charge do metal ions often carry? Positive 2 of 31 Why are ionic solids not able to conduct electricity? Ions=locked in place by bonds->Cannot move->NoConduction 3 of 31 How do we make ionic compounds conduct? When melted or dissolved, ions can move. Therefore conduct. 4 of 31 Describe what is meant by electrolysis. Electric current through l/aq IC->It breaks down to its elements 5 of 31 What is an electrolyte? l/aq ionic compound that an electric current goes through 6 of 31 What does OILRIG stand for? Oxidation Is Loss, Reduction Is Gain 7 of 31 How do we plate objects in metal? Make the object the negative electrode. + attracted to -. 8 of 31 The electrolyte needs to contain ions of a plating metal. Give an example of that electrolyte. Copper sulfate solution. 9 of 31 How do we extract the aluminium from its ore? Smelt it at the high melting point of 2000oC 10 of 31 Why is this expensive? Because it uses a large amount of energy. 11 of 31 How do we reduce the costs? Al2O3 is dissolved in cryolite to lower the melting pt and energy 12 of 31 What do the aluminium ions do at the negative electrode? They gain 3 electrons forming aluminium metal (REDUCTION) 13 of 31 What do the oxygen ions do at the positive electrode? They lose 2 electrons forming oxygen gas. 14 of 31 What are the electrodes made out of? Carbon graphite 15 of 31 What is therefore produced when the oxygen ions become oxygen gas? Carbon dioxide because the oxygen reacts with the carbon. 16 of 31 Why do the electrodes need top be changed regularly? The carbon graphite electrode reacts with the oxygen gas. 17 of 31 Give the half equation of aluminium at the negative electrode. Al3+ + 3e- --> Al (REDUCTION) 18 of 31 Give the half equation of oxygen at the positive electrode. 2O2- --> O2 + 4e- (OXYDATION) 19 of 31 Why is 2 oxygen ions written? Oxygen is a diatomic particle. O2 20 of 31 Why is it the ionic compound is dissolved in solution? We have to take into account the ions in water. 21 of 31 Give an example of why. H+ and Na+ are both +ve. We have to decide which one. 22 of 31 How do we decide which one is attracted to the electrode? The hydrogen is attracted if it's less reactive than the metal. 23 of 31 In NaCl, is hydrogen or sodium attracted to the negative electrode? Hydrogen. 24 of 31 At the positive electrode which type of ions are attracted? Halide ions and not the hydroxide OH- ion. 25 of 31 In NaCl, is the chloride or the hydroxide ion attracted to the positive electrode. Chloride 26 of 31 What is chlorine gas used for? Plastics and bleach. 27 of 31 What is left in the solution after electrolysis? Na+ and OH-. Therefore meaning sodium hydroxide solution. 28 of 31 What is sodium hydroxide used for? To make soap. 29 of 31 Give the half equation at the negative electrode. 2H+ + 2e- --> H2 (REDUCTION) 30 of 31 Give the half equation at the positive electrode. 2CL- - 2e- --> Cl2 2CL- --> CL2 + 2e- 31 of 31
All of chemistry revision sections C1,C2,C3,C4,C5,C6 :)) 5.0 / 5 based on 1 rating Teacher recommended
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