Redox reactions

Question 1

What’s oxidation and what’s reduction

Answer 1

oxidation = loss of electrons, gain of oxygen
Reduction = gain of electron , removal of oxygen

Question 2

When does oxidation and reduction happen ?
Example

Answer 2

at the same time .

Iron atoms are oxidised to Fe^2+ ions when they react with dilute acid Fe + big 2 H^+ -> Fe^2+ + h2

The iron atoms lose electrons. They’re oxidised by the hydrogen ions. Fe - big 2 e^-1 -> Fe^2+

The hydrogen ions gain electrons . They’re reduced by the iron atoms: Big 2 H ^+ + 2e^- -> H2

Question 3

Displacement reactions are

Answer 3

redox reactions

1) displacement reactions involve one metal kicking one out of a compound
2) If you put a reaction metal into the solution of a dissolved metal compound, the reactive metal will replace the less reactive metal in the compound

Question 4

Rule of displacement

Answer 4

A more reactive metal will displace a less reactive metal from its compound

Question 5

Example of displacement reaction

Answer 5

If you put iron in a solution of CuSO4, the more reactive iron will ‘kick out’ the less reactive copper from the solution. You can end up with FeSO4 and copper metal

Fe(s) + CuSO4 ( aq) -> FeSO4( aq) + Cu (s)

In this reaction, iron loses 2 electrons to become 2+ ion = oxidised . Fe -> Fe^2+ +big 2 e^-
The copper ion gains these 2 electrons to become a copper atom = its reduced
Cu^2+ + big 2 e^- -> Cu

Question 6

What occurs in a displacement reaction ?

Answer 6

always the metal ion that gain electrons and is reduced. Metal atom always loses electrons and is oxidised

Question 7

In an ionic equation, only the

Answer 7

particles that react and the products they form are shown, For example, Mg(s) + Zn^2+ (aq) -> Mg^2+ (aq) + Zn (s)

This shows the displacement of zinc ions by Magnesium metal. The full equation
Mg(s) + Zncl2+ (aq) -> Mgcl2+ (aq) + Zn (s)
If you write out the equations, you can see all the ions and see chloride ions don’t change = spectator ion, they’re are of no interest so can be crossed out.
Mg(s) + Zn^2+ (aq) + big 2 Cl^- ( aq) -> Mg^2+ (aq) + big 2 Cl^- ( aq) + Zn (s)

Instead, the ionic equation of this displacement reaction just concentrates of the substances which are oxidised or reduced.