Salts are sulphates, carbonates, nitrates, chromates etc but we want to look at the decomposition of a particular set of salts called nitrates.
It is important to note that salts are formed when the ionizable hydrogen ion from an acid has been completely or partially replaced by a metallic or ammonium ion.
The nitrates of metals decompose differently and it is important to study the decomposition of these salts so we can be able to write the chemical equations.
Decomposition of Group 1 Nitrates
Examples are Potassium nitrate (KNO3), Sodium nitrate (NaNO3), lithium nitrate (LiNO3).
2KNO3 –——– 2KNO2 + O2
2NaNO3 ——- 2NaNO2 + O2
2LiNO3 ——— 2LiNO2 + O2
Please remember that there are other groups I metal nitrates just that the metals are somewhat radioactive.
The other examples of group I metal nitrates are rubidium nitrate, caesium nitrate, francium nitrate.
The nitrates of group I decompose with difficulty to release oxygen and form dioxonitrates III salts
Decomposition of Group II Nitrates
The group II nitrates decompose differently from group 1 nitrates. The group II nitrates decompose to release oxygen, brown nitrogen iv oxide and form the oxide of the group II metal.
Examples are calcium nitrate, magnesium nitrate, strontium nitrate,
Mg(NO3)2 —–2MgO +4NO2 + O2
Ca(NO3)2 —–2CaO +4NO2 + O2
Ba(NO3)2 —–2BaO +4NO2 + O2
Decomposition of group III Nitrates
The group 3 elements or metals are Aluminium, Gallium etc but their nitrates include Al (NO3)2, , Ga(NO3)2.
How do these compounds decompose?
Actually Group 3 elements decompose the same way group II nitrates decompose, so lets look at some examples of the decomposition of group 3 Nitrates.
4Al(NO3)2 ——– 2Al2O3 +12 NO2 + 3O2
4Ga(NO3)2 ——2Ga2O3 +12NO2 + 3O2
Decomposition transition metals nitrates
Some of these transition metals’ nitrates decompose just like the group II nitrates.
Examples of these nitrates include copper II nitrates and iron II nitrates.
Cu(NO3)2 —–2CuO +4NO2 + O2
4Fe(NO3)3 —–2Fe2O3+12NO2 + 3O2
- Decomposition of metals lower than hydrogen
Some precious metals that are only mined like Silver and gold can be gotten from the decomposition of their nitrates.
2AuNO3 ——2Au + 2NO2 + O2
2AgNO3 ——2Ag + 2NO2 + O2