Topic 3 - displacement reactions

Question 1

Displacement reactions of metals​

Answer 1

A more reactive metal will displace a less reactive metal in a salt solution​

E.g. Iron + copper sulfate​

Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)​
0 +2 +6 (4x-2) +2 +6 (4x-2) 0 oxidation states​
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The solution will lose it’s colour as the copper ions are used up​

There will also be a pink-brown solid formed as the copper is displaced​

The iron has been oxidised and the copper has been reduced​

Question 2

Displacement reactions of Halogens​

Answer 2

Halogens (Group 7) are OXIDISING AGENTS which means they withdraw electrons from another atom or ion (the are very electronegative)​

The oxidising power of a halogen decreases as you go down the group

Question 3

Displacement of Bromine by Chlorine

Answer 3

If Chlorine reacts with potassium bromide, the bromine is displaced and potassium chloride is formed​

Cl2 + 2KBr → 2KCl + Br2​  0        +1 -1           +1 -1       0​

This is because chlorine is a stronger oxidising agent than bromine (higher up the group) so will withdraw an electron from the bromide ion​

Chlorine is reduced (gains an electron)​

Bromine is oxidised (loses an electron)

Question 4

Uses and applications of substances

Answer 4

The choice of a substance for a specific application will depend on the physical and chemical properties of the elements or compounds available

Question 5

Examples

Answer 5

Metal and non-metal oxides have a wide range of uses:​
Magnesium oxide is used as a starting material for producing magnesium alloys and fibreglass (magnesium itself is reactive so harder to store and transport)​

Metal salts are used in fireworks:​
Different metals burn with different coloured flames​

Sodium chloride has a wide range of uses:​
Manufacturing glass, paper and rubber and used in water softening systems (NaCl is cheap and readily available, individual elements are reactive, toxic and expensive)

Sulfates are used in detergents
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Copper sulfate is used in water treatment to kill algae​

Metal salts are used for treating mineral deficiencies