Explain why the positive carbon electrodes must be continually replaced.[3 marks]

Why does the positive anode need regular replacement in extraction of Aluminium from Al2O3?1 markAnode gains weightAnode dissolves in electrolyteAnode reacts with carbon to form carbon dioxideAnode becomes resistant to electricity

Which electrode is labeled as positive in a voltaic cell?Group of answer choicesboth anode and cathodeneither anode nor cathodeanode onlycathode only

Which of the following best explains why a chemical cell (or battery) stops working?The wire connecting the electrodes has brokenOne of the reactants has run outThe electrolyte has run outIt has overheatedCHECK YOUR ANSWERS

Which of the following statements about ‘inert’ electrodes is not true?At the cathode, positive ions gain electrons to become metal elementsThey take part in the electrolysis reactionsThey can be made of carbonAt the anode, negative ions lose electrons and become non-metal elements2Copper can be purified by electrolysis using metal (non-inert) electrodes. Which of the following correctly describes how the electrolysis cell should be set up?Cathode should be impure copper, anode should be pure copperCathode should be carbon, anode should be impure copperCathode should be pure copper, anode should be carbonCathode should be pure copper, anode should be impure copper3What happens at the anode?Copper ions formCopper atoms formSulfate ions formImpurities from the impure copper are collected4What happens at the cathode?Impurities from the impure copper are collectedCopper ions formSulfate ions formCopper atoms form5The core practical investigates the changes in electrode mass during the electrolysis of copper sulfate solution at different currents. Which of the following would you not expect to happen?The higher the current the lower the change in mass between the anode and cathodeThe anode decreases in massThe gain in mass by the cathode is the same as the loss in mass by the anodeThe cathode increases in mass6Sometimes the mass gain at the cathode may be slightly lower than the mass loss at the anode. What is an explanation for this?Some of the propanone used in the washing process may not have evaporated properly from the anodeAll of theseSome of the copper deposited at the cathode may have fallen off during the washing processIf the anode is not pure copper, any impurities will be deposited in the electrolyte rather than at the cathode

__________ is an electrode connected to the positive terminal of the external voltage.