Difference between revisions of "Half Equation"
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| style="height:10px; width:200px; text-align:center;" |4OH<sup>-</sup> → 2H<sub>2</sub>O(l) + O<sub>2</sub>(g) + 4e<sup>-</sup> | | style="height:10px; width:200px; text-align:center;" |4OH<sup>-</sup> → 2H<sub>2</sub>O(l) + O<sub>2</sub>(g) + 4e<sup>-</sup> | ||
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| + | ===References=== | ||
| + | ====AQA==== | ||
| + | |||
| + | :[https://www.amazon.co.uk/gp/product/1471851346/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851346&linkCode=as2&tag=nrjc-21&linkId=3ac654f4b0da781c49c855a1af4c92ea ''Half equations, pages 104, 289-91, GCSE Chemistry, Hodder, AQA ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/178294639X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294639X&linkCode=as2&tag=nrjc-21&linkId=51599bb45a2bfaf7c1b6a978b2ca2616 ''Half equations, pages 142-144, GCSE Combined Science Trilogy; Chemistry, CGP, AQA ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/1782945962/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945962&linkCode=as2&tag=nrjc-21&linkId=476bb5c8d1dfb5c08ac81b6d4d1c98d8 ''Half equations, pages 167-169, GCSE Chemistry, CGP, AQA ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Half equations, pages 206, 255-7, GCSE Combined Science Trilogy 1, Hodder, AQA ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/1782945571/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945571&linkCode=as2&tag=nrjc-21&linkId=9e29fad914244909903e5e93f8a01d150 ''Half equations, pages 59, 65, GCSE Chemistry; The Revision Guide, CGP, AQA ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Half-equations, pages 87, 104-105, 107, 108, 123, GCSE Chemistry; Third Edition, Oxford University Press, AQA ''] | ||
Revision as of 08:17, 6 November 2019
Key Stage 4
Meaning
A half equation is a type of symbol equation which shows how individual ions gain or lose electrons at an electrode during electrolysis.
About Half Equations
- In half equations only one ion is considered at a time, or the changes at one electrode.
- Half equations use the letter 'e' to represent electrons.
- Half equations can be taken from balanced symbol equations.
- The total charge on each side of a half equation must add to zero.
- The number of each element must be the same on both sides of a half equation.
Examples
| Balanced Symbol Equation | 2Li2O(l) → 4Li(l) + O2(g) | CuCl2(aq) → Cu(s) + Cl2(g) | 2H2O(l) → 2H2(g) + O2(g) |
| Half Equation at cathode | Li+ + e- → Li | Cu+2(aq) + 2e- → Cu(s) | 2H+(aq) + 2e- → H2(g) |
| Half Equation at anode | 2O-2 → O2 + 4e- | 2Cl-(aq) → Cl2(g) + 2e- | 4OH- → 2H2O(l) + O2(g) + 4e- |
References
AQA
- Half equations, pages 104, 289-91, GCSE Chemistry, Hodder, AQA
- Half equations, pages 142-144, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
- Half equations, pages 167-169, GCSE Chemistry, CGP, AQA
- Half equations, pages 206, 255-7, GCSE Combined Science Trilogy 1, Hodder, AQA
- Half equations, pages 59, 65, GCSE Chemistry; The Revision Guide, CGP, AQA
- Half-equations, pages 87, 104-105, 107, 108, 123, GCSE Chemistry; Third Edition, Oxford University Press, AQA