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Description
Flashcards by Jamine Shaw, updated more than 1 year ago
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Created by Jamine Shaw
about 6 years ago
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| Question | Answer |
| Electrolysis | The breaking down of a molton or aqueous ionic compound using electricity |
| Molten on the left. Solution on the right | Ionic compounds are made up of positive and negative ions. But in order for them to conduct electricity, they have to be able to move around. |
| Why does the ionic compound have to be in liquid form? | Solid ions are fixed in place and cannot move and carry charge. In liquid form, the charged particles can move past each other and therefore conduct electricity. |
| Electrolysis of a molten ionic compound | Example: lead bromine, starts off solid in the ionic compound. The compound is heated to turn the lead bromide into a molten form. After heating, the electric current is flowing, and the negative ions are attracted to the anode, whereas the positive ions are attracted to the cathode. As a result, the compound breaks apart: lead forms at the cathode and bromine forms at the anode |
| Equations for what happens at each electrode: half equations At the anode | Equation: PbBr2(l) -->Pb(l/s) + Br2(g). Half equations. At the anode: non-metal will always form at anode. The bromine forms here, and so start of with Br-. But as there are 2, we have to balance out the equation: 2Br- -->Br2 + We then have to balance out the negative charge by adding 2 electrons, taken from the electric flow. 2Br- -->Br2 + 2e- |
| Half equations At the cathode | The metal will always be attracted to the cathode. This time we start with Pb2+. On this side the lead ions are gaining two electrons: Pb2+ + 2e- They then form the lead metal: Pb2+ + 2e- --> Pb |
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