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Electrolysis C4 - Coggle Diagram
Electrolysis C4
Electroplating
Electrolysis is used to coat cheaper metal in more expensive ones by coating them with a thin layer of metal
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Electrolysis
Ionic substances
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For example, lead bromide contains positively charged lead ions and negatively charged bromide ions
Electrolysis is the process in which ionic substances are broken down into simpler substances when electricity is passed through them.
Electricity is the flow of electrons or ions, for electrolysis to work, the compound must contain ions
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The ions must be free to move, which happens when an ionic substances is melted or dissolved in water
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Electrolytes
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Testing for conductivity - include a sample of the substance in a circuit of direct current and an ammeter - if the current flows through the substance when it is molten or dissolved, its an electrolyte
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Electrolysis cont.
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Ionic solutions
Electrolysing aqueous solutions of ionic compounds is more complicated because water molecules can provide hydrogen and hydroxide ions
Negative (Cathode) electrode - Metal and hydrogen ions are both positively charged - whats formed depends on the reactivity series
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Positive electrode (Anode) - If the ion is simple (Cl-, Br-) then that will form but if the ion is complex (SO42-) then oxygen from the hydroxide forms
Common - substance, negative electrode, positive electrode
Copper chloride, CuCl2 Copper, Cu Chlorine, Cl2
Copper sulfate, CuSO4 Copper, Cu Oxygen, O2
Halide
If a halide solution is very dilute, then the oxygen will be given off insteal of the halogen as the halide ions are outnumbered by the hydroxide ions
Purifying copper
- A beaker with a pure and impure copper rod are dipper into copper sulfate solution
- The pure copper rod is connected to the negative terminal of the battery and the impure to the potitive
- The pure copper rod increases in size, while the impure deteriorates
