Ammonia

Preparation

1. Ammonia gas (NH3) can be conveniently prepared in the laboratory by heating together an ammonium salt with a strong alkali e.g.

Ca(OH)2 (s) + 2 NH4Cl (s) -> CaCl2 (s) + 2 H2O (l) + 2 NH3 (g)

2. Ammonia can be collected by the downward displacement of air since it is lighter than air
3. Ammonia cannot be collected by the displacement of water because it is very soluble in water
4. Ammonia can be collected through the Haber Process

Properties of Ammonia

• Colourless
• Strong choking smell
• Less dense than air
• Liquefies at -33°C. This makes it easy to transport and store as a liquid
• Extremely soluble in water, as it is a polar molecule and can hydrogen bong with itself and water molecules, to produce an alkaline solution
• The only common alkaline gas

Uses of Ammonia

• Making nitric acid

• Making fertilisers such as urea, ammonium nitrate, and ammonium sulphate
• Household cleaners
• Dyes
• Explosives

Urea Production

Urea – an important nitrogenous (nitrogen containing) fertiliser. It is a white, water-soluble solid. Urea is less soluble than inorganic fertilisers and so releases the nitrogen slowly to plants; CO(NH2)2. The process occurs at 190°C and 230 atm.

CO2 (g) + 2 NH3 (g) -> CO(NH2)2 (s) + H2O (g)