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Ammonia
Are produced from nitrogen reacted with hydrogen (Haber process).
Used for producing: fertilisers, nitric acid, nylon, dyes, cleaners and dry
cell.
Objectives:
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Describe the use of nitrogen, from air, and hydrogen, from cracking
oil, in the manufacture of ammonia.
Describe and explain the essential conditions for the manufacture of
ammonia by the Haber process.
The Manufacture of Ammonia: The Haber Process
The Process
Nitrogen and hydrogen are mixed together in ratio 1:3, where nitrogen is
obtained from fractional distillation of liquid air and hydrogen is obtained
from natural gas (methane) with steam, or from cracking oil fractions, and
passed over iron catalyst.
Properties and Uses of Ammonia
Physical properties:
 Colourless gas
 Characteristic pungent smell
 Non-poisonous, but can have adverse effects on the respiratory
system if inhaled in large quantities
 Lighter than air
 Easily liquefiable even at low temperatures
 Boiling point –33.5° C
 Freezing point – 77.7° C
 Highly soluble in water
 Causes irritating burning sensation in nasal passage.
Haber process Equation
Since the reaction is reversible so H2 and N2, reproduced from
decomposition of produced NH3, are passed over the catalyst again to
produce ammonia.
Ammonia as Fertilizers
Objectives:
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Ammonia
and its Uses
Page 1 of 2
Describe the use of nitrogenous fertilisers in promoting plant
growth and crop yield.
Compare nitrogen content of salts used for fertilisers by calculating
percentage masses.
Describe eutrophication and water pollution problems caused by
nitrates leaching from farm land and explain why the high solubility
of nitrates increases these problems.
Describe the displacement of ammonia from its salts and explain
why adding calcium hydroxide to soil can cause the loss of nitrogen
from added nitrogenous fertiliser.
Chemistry Dept/Grade9/First Term/2014
Imaduddin School
Plants need nitrogen as one of component for growth and ammonium
fertilizers contain Nitrogen for that.
groundwater is our drink source, when humans drink this water, they will
get seriously ill and babies may suffer breathlessness to death.
The Effect of Calcium Hydroxide Ammonium Fertilizer on Soil
Soil that is too acidic presents different problems for crops.
Calcium hydroxide, which is produced by adding water to calcium oxide,
neutralises the acidity of the soil by reacting but it also react with
ammonium fertilizers. So, Nitrogen is lost as ammonia gas escape fro m the
soil.
2NH4NO3+ Ca(OH)2 --> 2NH3(g) + Ca(NO3)3 + 2H2O
Chemical properties of Ammonia
Problems with Ammonia
Eutrophication is the inrease in organic content of water when fertilizers
leach into soil and washed into rivers and streams.
 When excess fertilizers washed away by rain, nitrate ions in it gets into
rivers and helps aquatic plants like algae to grow swiftly.
 When too much algae, water turns murky and sunlight would not
penetrate into water to help their growth which in turn lead to deaths
of algae.
 Decay of these algae uses up oxygen, hence killing aquatic animals.
Then even more algae dies and even more animals die.
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Gives white fumes with hydrochloric acid
Alkaline gas (turns red litmus paper blue)
Neither combustible nor a supporter of combustion
Highly soluble in water
Forms salts with acids
Reduces metal oxides to free metals
Reacts with carbon dioxide to form urea
Forms a pale blue copper hydroxide with copper sulphate
Reduces halogens to halide ions
Forms complex compounds with aqueous solutions of salts of copper or
silver
Water pollution results from runoff of fertilizer use, leaching from septic
tanks, sewage and erosion of natural deposits. Nitrate ions from nitrogen in
soil leaches down the soil into groundwater due to its solubility. Since
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Chemistry Dept/Grade9/First Term/2014
Imaduddin School