SASS Chem Electrolysis AfL

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY (G3) 6092 14.1 Electrolytic Cells ELECTROLYSIS Assessment for Learning 1 Metal M forms the chloride MCl2. M is found between copper and silver in the reactivity series. Which reaction would occur at the anode and at the cathode, of which both are inert, used during the electrolysis of a concentrated aqueous solution of MCl2? Anode Cathode A 2 Cl – ® Cl2 + 2 e – M+ + e – ® M B 2 Cl – ® Cl2 + 2 e – M2+ + 2 e – ® M C 4 OH – ® 2 H2O + O2 + 4 e – M+ + e – ® M D 4 OH – ® 2 H2O + O2 + 4 e – M2+ + 2 e – ® M 2 In which electrolyte would the cathode used increase in mass during electrolysis? A Aqueous copper(II) sulfate B Concentrated aqueous sodium chloride C Concentrated hydrochloric acid D Dilute sulfuric acid 3 Inert electrodes are used in the electrolysis of an aqueous solution containing both CuSO4 and MgSO4. What would be the product formed at the negative electrode? A Copper B Hydrogen C Magnesium D Oxygen 4 What happens when molten barium chloride is electrolysed using inert electrodes? A Ba2+ ions gain electrons at the anode. B Ba2+ ions lose electrons at the cathode. C Cl – ions gain electrons at the anode. D Cl – ions lose electrons at the cathode. 5 What would be observed during the electrolysis of aqueous copper(II) sulfate using carbon electrodes? A A pink-brown solid is deposited at the anode. B Bubbles form at the negative electrode. C The colour of the solution fades. D The negative electrode becomes smaller.

Page 2 6 The diagram shows the electrolysis of concentrated aqueous sodium chloride. What would be the colour of the litmus at each electrode after five minutes? Colour at anode Colour at cathode A Blue Red B Colourless Blue C Red Colourless D Red Blue 7 The electrolysis of a molten compound using inert electrodes would form two atoms of X at the negative electrode and three atoms of Y at the positive electrode. Which row is correct? X is a Y is a Chemical formula of compound A metal non-metal X2Y3 B metal non-metal X3Y2 C non-metal metal X2Y3 D non-metal metal X3Y2 8 The bulb lights with a gas produced at each electrode could be observed during this experiment. What is X? A Aqueous copper(II) sulfate B Concentrated aqueous sodium chloride C Ethanol D Molten lead(II) bromide 5 © UCLES 2012 5070/11/O/N/12 [Turn over 11 Which statement about the particles O2–, F–, Ne, Na+ and Mg2+ is true? They all A contain more electrons than protons. B contain more neutrons than protons. C contain the same number of electrons. D contain the same number of neutrons. 12 T h e Mr of oxygen, O2, is 32 and the Mr of sulfur is 256. What is the formula of a molecule of sulfur? A S2 B S4 C S8 D S16 13 In the experiment shown in the diagram, the bulb lights and a gas is produced at each electrode. bulb +ve –ve X inert electrodes What is X? A a q u e o u s c o p p e r (II) sulfate B concentrated aqueous sodium chloride C e t h a n o l D molten lead bromide 14 Which element in the table is an alkali metal? melting point °C density g / cm3 A –39 13.60 B –7 3.10 C 98 0.97 D 1083 8.92 www.maxpapers.com 7 © UCLES 2013 0439/11/O/N/13 [Turn over 12 T h e d i a g r a m s h o w s t h e e l e c t r o l y s i s o f c o n c e n t r a t e d a q u e o u s s o d i u m c h l o r i d e . +–anode cathode concentrated aqueous sodium chloride and litmus carbon rods What is the color of the litmus at each electrode after five minutes? color at anode color at cathode A blue red B red blue C red colorless D colorless blue 13 When anhydrous copper(II) sulfate is added to water a solution is formed and heat is given out. water anhydrous copper(II) sulfate thermometer Which row correctly shows the temperature change and the type of reaction taking place? t e m p e r a t u r e c h a n g e t y p e o f r e a c t i o n A decreases endothermic B decreases exothermic C increases endothermic D increases exothermic

Page 3 9 Four different solutions were electrolysed in separate experiments. In one of the experiments, X2 was formed at the anode. For which combination of solution and electrodes can the reaction for the formation of X2 be represented by the equation shown below? 2 X – ® X2 + 2 e – A Aqueous copper(II) sulfate with copper electrodes B Aqueous copper(II) sulfate with inert electrodes C Concentrated aqueous sodium chloride with inert electrodes D Dilute aqueous sodium chloride with inert electrodes 10 Aqueous copper(II) sulfate is electrolysed using carbon electrodes. Which pair of ionic equations represent the reactions at the electrodes? 1 Cu2+ + 2 e – ® Cu 2 Cu ® Cu2+ + 2 e – 3 2 H+ + 2 e – ® H2 4 4 OH – ® 2 H2O + O2 + 4 e – A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4 10 © UCLES 2008 5070/01/O/N/08 29 W h i c h p r o p e r t y w o u l d a l l t h e h y d r o g e n c o m p o u n d s o f t h e G r o u p V I I e l e m e n t s p o s s e s s ? A b e c o v a l e n t B be solids at room temperature C form alkaline aqueous solutions D conduct electricity when molten 30 A q u e o u s c o p p e r (II) sulphate is electrolysed using inert electrodes as shown. carbon electrode aqueous copper(II) sulphate carbon electrode Which ionic equations show the reactions at the electrodes? 1 Cu2+ + 2e– → Cu 2 Cu → Cu2+ + 2e– 3 2H+ + 2e– → H2 4 4OH– → 2H2O + O2 + 4e– A 1 and 2 only B 1 and 4 only C 2 and 3 only D 3 and 4 only 31 The element chromium liberates hydrogen from dilute hydrochloric acid although it does not react with cold water. When a piece of chromium is placed in lead(II) nitrate solution, crystals of lead appear. What is the order of decreasing reactivity of the metals lead, calcium and chromium? A calcium, chromium, lead B calcium, lead, chromium C chromium, calcium, lead D lead, chromium, calcium solution electrodeelectrode 10 © UCLES 2008 5070/01/O/N/08 29 W h i c h p r o p e r t y w o u l d a l l t h e h y d r o g e n c o m p o u n d s o f t h e G r o u p V I I e l e m e n t s p o s s e s s ? A b e c o v a l e n t B be solids at room temperature C form alkaline aqueous solutions D conduct electricity when molten 30 A q u e o u s c o p p e r (II) sulphate is electrolysed using inert electrodes as shown. carbon electrode aqueous copper(II) sulphate carbon electrode Which ionic equations show the reactions at the electrodes? 1 Cu2+ + 2e– → Cu 2 Cu → Cu2+ + 2e– 3 2H+ + 2e– → H2 4 4OH– → 2H2O + O2 + 4e– A 1 and 2 only B 1 and 4 only C 2 and 3 only D 3 and 4 only 31 The element chromium liberates hydrogen from dilute hydrochloric acid although it does not react with cold water. When a piece of chromium is placed in lead(II) nitrate solution, crystals of lead appear. What is the order of decreasing reactivity of the metals lead, calcium and chromium? A calcium, chromium, lead B calcium, lead, chromium C chromium, calcium, lead D lead, chromium, calcium sulfate

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY (G3) 6092 14.2 Simple Cells ELECTROLYSIS Assessment for Learning 1 The diagram shows a simple cell. Which pair of metals X and Y would give the smallest reading on the voltmeter? X Y A Mg Cu B Mg Fe C Zn Cu D Zn Fe 2 Which pair of metals X and Y would produce the largest voltage in the simple cell shown? X Y A Cu Ag B Mg Ag C Mg Zn D Zn Cu [Turn Over CHEMISTRY (G3) 6092 MARKING SCHEME Section A [5 Marks] 1 2 3 4 5 D B B D C Section B Qn Answers Mark Remarks 6 (a)(i) A and H [1] 6 (a)(ii) B [1] 6 (a)(iii) D [1] 6 (a)(iv) C and E or C and G [1] 6 (b) F F contains 10 electrons arranged in 3 electron shell