Redox reactions Flashcards
What makes a ‘‘Redox reaction’’?
when electrons are transferred by oxidation or reduction
What is oxidation?
A loss of electrons
What is reduction?
A gain of electrons
Where does the word ‘‘REDOX’’ come from?
REDuction and OXidation.
(The R-E-D from reduction and the O-X from oxidation_
Is chlorine gas reacting with iron (II) salt an oxidation or reduction reaction? Why.
It is an oxidation reaction
The solution turns from green to yellow where the iron (II) is OXIDISED into iron(III) (lost an electron)
Give me the symbol equation of chlorine gas reacting with iron(II) salt. Explain which element is an oxidising agent and a reducing agent.
In here, the iron(II) turned into iron(III):
Fe2+ - e- —> Fe3+
The chlorine caused this to happen (this makes the chlorine the oxidising agent), but what happens to the chlorine is this:
1/2Cl2 + e- —> Cl-
Above is the chlorine gaining an electron (reduction) which the iron(II) gave away to make iron(III). This makes the Iron(II) the reducing agent.
With what types of acid are iron atoms oxidised to iron(II)?
Dilute acid
When iron(II) is reacting with dilute acid, what atoms get oxidised?
The iron atoms
Which atoms are oxisided and which are reduced when iron(II) reacts with a dilute acid?
Iron atoms are oxidised (lose an electron) - this is caused by the hydrogen atoms
Hydrogen ions gain electrons (reduction) - This is caused by the iron atoms.
Write down the symbol equation of iron(II) reacting with a dilute acid.
Fe - 2e- —> Fe2+
The equation above shows iron(II) going through oxidation (losing 2 electrons)
2H+ + 2e- —> H2
The equation above shows the hydrogen ion molecule going through reduction (gaining 2 electrons)
What are displacement reactions?
Involves 1 MORE reactive metal kicking/displacing a LESS reactive metal from its compound
E.g. a reactive metal in a solution with a dissolved metal compound will REACT. Where the reactive metal will replace the less reactive metal in the compound (solution)
Give me the order of metals starting from the least reactant one. (Start with tin)
Magnesium
Zinc
Iron
Tin
Give me an example of a displacement reaction, using iron.
Iron reaction with tin(II) sulfate. Where iron is more reactive that tin.
End up with -
Iron(II) sulfate solution + tin
OR
FeSO4(aq) + Sn(s)
What happens to the tin and ion, in a displacement reaction, when they produced “iron(II) sulfate and tin metal”
Iron :
2-
Fe + SO. —> FeSO + 2e-
4. 4
Above :
Iron is oxidised and gains 2 electrons
Tin:
Sn2+ + 2e- —-> Sn
Above:
Tin is reduced and gains 2 electrons to become a tin atom (not an ion anymore- has no charge)
What happens to a metal ion in a displacement reaction?
It always gets reduced (gains electrons)
