Difference between revisions of "Half Equation"
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: '''Half equations''' use the letter 'e' to represent [[electron]]s. | : '''Half equations''' use the letter 'e' to represent [[electron]]s. | ||
: '''Half equations''' can be taken from [[Balanced Symbol Equation|balanced symbol equations]]. | : '''Half equations''' can be taken from [[Balanced Symbol Equation|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=== | ===Examples=== | ||
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'''Half Equation''' at [[anode]]: 2O<sup>-2</sup> → O<sub>2</sub> + 4e<sup>-</sup> | '''Half Equation''' at [[anode]]: 2O<sup>-2</sup> → O<sub>2</sub> + 4e<sup>-</sup> | ||
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| + | {| class="wikitable" | ||
| + | | style="height:20px; width:150px; text-align:center;" |[[Balanced Symbol Equation]] | ||
| + | | style="height:20px; width:150px; text-align:center;" |2Li<sub>2</sub>O → 4Li + O<sub>2</sub> | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | |||
| + | |||
| + | |- | ||
| + | | style="height:20px; width:150px; text-align:center;" |'''Half Equation''' at [[cathode]] | ||
| + | | style="height:20px; width:150px; text-align:center;" |Li<sup>+</sup> + e<sup>-</sup> → Li | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | |||
| + | |- | ||
| + | | style="height:20px; width:150px; text-align:center;" |'''Half Equation''' at [[anode]] | ||
| + | | style="height:20px; width:150px; text-align:center;" |2O<sup>-2</sup> → O<sub>2</sub> + 4e<sup>-</sup> | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | | style="height:20px; width:150px; text-align:center;" |Text | ||
| + | |||
| + | |} | ||
Revision as of 07:16, 3 January 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 → 4Li + O2
Half Equation at cathode: Li+ + e- → Li
Half Equation at anode: 2O-2 → O2 + 4e-
| Balanced Symbol Equation | 2Li2O → 4Li + O2 | Text | Text
|
| Half Equation at cathode | Li+ + e- → Li | Text | Text |
| Half Equation at anode | 2O-2 → O2 + 4e- | Text | Text |