Question

derive the molecular formulae for the following compounds: 1.copper(II) bromide. 2.ammonium carbonate. 3.aluminium oxide.

Answer 1

1.copper(II) bromide=CuBr2
valency of copper=+2
valency of bromide= -1,crossmultiplication you get CuBr2

2.ammonium carbonate=(NH4)2CO3
valency of ammonium=+1
valency of CO3= -2,crossmultiplication

3.aluminium oxide=Al2O3
valency of aluminium= -2
valency if oxide=+3,crossmultiply.
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Answer 2

1. Valency of Copper (||) = +2
Valency of Bromine (Bromide) [Br] = 1 Therefore, by cross multiplying both the valencies
Molecular Formula of Copper (||) Bromide = CuBr2

2. Valency of Ammonia (Ammonium) [NH4] = 1+
Valency of Carbonate = (CO3) = -2
Therefore, by cross multiplying
Molecular Formula of Ammonium Carbonate = NH4(2)CO3

3. Valency of Aluminium (Al) = -2
Valency of Oxide (O) = +3
Therefore, by cross multiply
Molecular formula of Aluminium Oxide = Al2O3