Topic 3 - displacement reactions Flashcards
Displacement reactions of metals
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
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
Displacement reactions of Halogens
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
Displacement of Bromine by Chlorine
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)
Uses and applications of substances
The choice of a substance for a specific application will depend on the physical and chemical properties of the elements or compounds available
Examples
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
Copper sulfate is used in water treatment to kill algae
Metal salts are used for treating mineral deficiencies