Redox
Introduced| English | Meaning |
|---|---|
| redox/rɪˈdɒks/ | A process in which oxidation and reduction occur together through changes in oxidation state. |
| oxidation/ˌɒksɪˈdeɪʃn/ | A chemical change involving a loss of electrons or an increase in oxidation state. |
| reduction/rɪˈdʌkʃn/ | A chemical change involving a gain of electrons or a decrease in oxidation state. |
| reducing agent/rɪˈdjuːsɪŋ ˈeɪdʒənt/ | A substance that donates electrons to another substance and is itself oxidised. |
| oxidising agent/ˈɒksɪdaɪzɪŋ ˈeɪdʒənt/ | A substance that accepts electrons from another substance and is itself reduced. |
| respiration/ˌrespɪˈreɪʃn/ | The chemical reactions in cells that release usable energy from nutrient molecules. |
| displacement/dɪˈspleɪsmənt/ | A reaction in which one element replaces another in a compound. |
Electron bookkeeping
- Many reactions involve electrons moving from one substance to another.
- These are redox 氧化还原 reactions — short for reduction and oxidation.
In terms of electrons, oxidation is:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
OIL: Oxidation Is Loss of electrons.
Oxidation and reduction:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Electrons lost by one are gained by another.
The memory aid for redox is OIL ______.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Oxidation Is Loss, Reduction Is Gain.
Oxidation 氧化 and reduction 还原
- Oxidation Is Loss of electrons; Reduction Is Gain of electrons (OIL RIG).
- The two always happen together: if one substance loses electrons, another gains them.
Electrons pass from the substance that is oxidised (loses them) to the one that is reduced (gains them) — OIL RIG
A hydrogen fuel cell runs on a redox reaction: hydrogen is oxidised and oxygen is reduced
Oxidation and reduction happen together
Step through a redox reaction. One substance loses electrons while another gains them — you can never have one without the other.
A reducing agent:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
A reducing agent donates electrons.
Oxidising and reducing agents 还原剂
- An oxidising agent 氧化剂 takes electrons (so it is itself reduced).
- A reducing agent gives electrons (so it is itself oxidised).
In terms of oxygen, oxidation is the gain of oxygen.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Reduction is loss of oxygen; oxidation is gain.
Redox in the world
- Many everyday reactions are redox: combustion, rusting, respiration 呼吸作用, and displacement 置换.
- In terms of oxygen, oxidation is gain of oxygen and reduction is loss of oxygen.
Worked example. When magnesium burns: Mg loses electrons (oxidised) and oxygen gains them (reduced). Magnesium is the reducing agent; oxygen is the oxidising agent. One reaction, both processes.
You've got it
- redox = reduction + oxidation, always happening together
- OIL RIG: Oxidation Is Loss, Reduction Is Gain of electrons
- an oxidising agent gains electrons; a reducing agent loses them