Carbon + oxygen → carbon dioxide
The carbon has gained oxygen and has been
CH₄ + 2O₂ → CO₂ + 2H₂O
The carbon has gained oxygen so has been
The hydrogen has gained oxygen so has been
CuO + H₂ → Cu + H₂O
The copper in Copper (II) oxide has lost oxygen and has been
The hydrogen has gained oxygen and has been
Mg +CuSO₄ → MgSO₄ + Cu
In a metal displacement reaction even though there has been no gain or loss of oxygen we can still identify what has been oxidised and what has been reduced.
The metal in the element has been oxidised.
The metal in the compound has been reduced.
Mg has been
The copper (in copper sulfate ) has been .
2K(s) + Br2(ℓ) → 2KBr(s)
The potassium atoms have lost electrons and been
This means that the bromide ions have been
K →K+ +e- (loss of electrons so )
2Br⁻ → Br₂ +2e⁻ (gain of electrons so )
In oxidation and reduction reactions for non-metals.
The non-metal atoms gain electrons to for negative ions and are therefore being .
The negative non-metal ions lose electrons and are therefore being
2I⁻ + Br₂ → I₂ + 2Br⁻
The iodide ions have lost electrons and have been
The chlorine atoms have gained electrons and have been
Oxidation and reduction can also be thought of in terms of the gain or loss of electrons.
Reduction is gain of electrons
Oxidation is loss of electrons
Cu²⁺ + 2e⁻ → Cu
The copper ions has been (gained electrons).
Mg →Mg²⁺ + 2e⁻
The magnesium metal atoms have been (lost electrons)
Zinc oxide + aluminium → aluminium oxide + zinc
The zinc in zinc oxide has lost oxygen and has been
The aluminium has gained oxygen and has been
Zn2+ + 2e⁻→ Zn
The zinc ions have gained electrons and have been
Al → Al3+ + 3e⁻
The aluminium atoms have lost electrons and have been
Iron oxide + aluminium → aluminium oxide + iron
The iron in iron oxide has lost oxygen and has been
The aluminium has gained oxygen and has been
To summarise
Oxidation is of oxygen or of electrons.
Reduction is of oxygen or of electrons.
Positive metal ions electrons and are to form neutral metal atoms.
e.g. Al3+ 3e- →Al (reduction)
Neutral non-metal atoms electrons and are to form negative non-metal ions.
Br₂ + 2e-→ 2Br⁻