The cell pushes from the anode to the cathode. At the same time, it pushes the around the wires (these electrons are already spread through the wires). Electrons in the cathode recombine with copper ions from the solution, forming a of copper atoms.
Gradually, the anode is eroded and the cathode grows. Insoluble impurities in the anode in a pile. This valuable bi product is removed.
Gold, silver, platinum and tin are insoluble in this and so do not deposit on the cathode. They form a 'sludge' that collects under the anodes.
If the substance the metal rods are placed in is not in liquid form, the current with not conduct.
To prove that electricity is flowing through the current, we could add a working bulb to the circuit. If the is a current flowing, the bulb will light up, but if there is no current flowing through the circuit, the bulb will not light up. This is shown in a diagram below.
However, if there is a current, but it is quite a low voltage, the bulb may not light up, despite there being an active current present. We could overcome this problem by adding an ammeter to the circuit. This would mean that the ammeter would be able to show us whether there was a current in the circuit, and how strong the current is.
An electrolyte is the substance that lets a current pass through itself, when in a liquid or solid state.
The chemical name for salty water is sodium chloride solution. In the seas and oceans there is lots of salty water. Sodium chloride solution is made up of four different ions:
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Na+ (sodium)
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H+ (hydrogen)
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Cl- (chlorine)
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OH- (hydroxyl)
The hydrogen and chlorine ions collect together to form hydrogen gas and chlorine gas. The hydrogen ions go to the negative electrode (cathode) and the chlorine ions go to the positive electrode (anode).
So, from just sea water, scientists can use electrolysis to make hydrogen gas, chlorine gas, and a solution of sodium hydroxide.
The process for extracting aluminium from aluminium oxide is an important industrial process. The aluminium oxide is extracted from bauxite by dissolving the rock in hot sodium hydroxide. The aluminium oxide dissolves and can be separated from the rock.
Aluminium
The aluminium oxide is a white solid but it does not melt very easily. In order to overcome this, it is dissolve in a molten rock called cryolite.The cell is lined with graphite (carbon) as the cathode, and graphite blocks are used as the anode. At the cathode aluminium is formed according to the equation:
Al3+ + 3e- ----------> Al
Aluminium ions plus electrons form aluminium atoms (i.e. metallic aluminium)
At the anode, the oxide ion reacts forming oxygen.
2O2- -----------> O2 + 4e-
Two oxide ions (with a charge of minus 2) form an oxygen molecule and 4 electrons. The oxygen produced will react with the graphite anode forming carbon dioxide, a gas, so the anode slowly disappears and needs to be replaced.
