SULPHURIC ACID1.0 Sulphuric acid

1.1 Uses of sulphuric acid

Car batteries contain sulphuric acid Sulphuric acid also used in which is used as the electrolyte. the making of artificial silk-like fibres

Chemical fertilizer such as ammonium Chemical like paints, dyes and drug sulphate and potassium sulphate.

Uses of sulphuric acid in daily life

1.2 The steps in the production of sulphuric acid by the Contact Process

STAGE1: Production Of Sulphur Dioxide From Sulphur

i.Combustion of sulphur or sulphide ores in the air produce sulphur dioxide SO2.

S(s)+O2(g) SO2(g)

ii. Sulphur dioxide is dried and purified.

STAGE2: Production Of Sulphur Trioxide From Sulphur Dioxide

i. The purified sulphur dioxide SO2 and excess air are passed over vanadium(V)

oxide V2O5 at controlled optimum condition optimum condition to produce sulphur

trioxide SO3. 2SO2(g)+O2(g) 2SO3(g)

ii. The optimum used are a) Temperature:450-500°C b) Pressure: 2-3 atmospheres c) Catalyst: Vanadium(V) oxide

iii. Under controlled optimum conditions, 98% conversion is possible. Sulphur dioxide and oxygen that

have not reacted are allowed to flow back again over the catalyst in the converter.

STAGE3: Conversion of trioxide to sulphuric acid

i. Sulphur trioxide SO2 is dissolved in concentrated sulphuric acid H2SO4 to form oleum H2S2O7 which is then diluted with water to form sulphuric acid H2SO4.

SO3(g)+H2SO4(l) H2S2O7(l) Oleum

H2S2O7(l)+ H2O(l) 2H2SO4(aq)

ii.The two reactions in stage3 are equivalent to adding sulphur trioxide directly into water.

SO3(g)+H2O(l) H2SO4(aq)

iii.The addition of sulphur trioxide directly into is not carried out because the reaction very vigorous, a lot

of heat is given off. As a result, a large cloud of sulphuric acid fumes is produced, which is corrosive

causes severe air pollution.

Manufacture of sulphuric acid by Contact Process - flow diagram

1.3 The Effects of Sulphur Dioxide

1.3.1 Main sources of sulphur dioxide

Sulfur dioxide is a gas. It is invisible and has a nasty, sharp smell. It reacts easily with other substances to form harmful compounds, such as sulfuric acid, sulfurous acid and sulfate particles.

About 99% of the sulfur dioxide in air comes from human sources. The main source of sulfur dioxide in the air is industrial activity that processes materials that contain sulfur, eg the generation of electricity from coal, oil or gas that contains sulfur. Some mineral ores also contain sulfur, and sulfur dioxide is released when they are processed. In addition, industrial activities that burn fossil fuels containing sulfur can be important sources of sulfur dioxide.

1.3.2 The effects of sulphur dioxide towards human health

Sulfur dioxide affects human health when it is breathed in. It irritates the nose, throat, and airways to cause coughing, wheezing, shortness of breath, or a tight feeling around the chest. The effects of sulfur dioxide are felt very quickly and most people would feel the worst symptoms in 10 or 15 minutes after breathing it in.

Those most at risk of developing problems if they are exposed to sulfur dioxide are people with asthma or similar conditions.

1.3.3 Formation of acid rain

Acid rain is caused by the release of the gases SO2 (sulphur dioxide) and NOX (nitrous oxides). The main sources of SO2 are coal-fired power stations and metal working industries. The main sources of NOX emissions are vehicles and fuel combustion.

Sulphur dioxide reacts with water vapour and sunlight to form sulphuric acid. Likewise NOX form nitric acid in the air. These reactions takes hours, or even days, during which polluted air may move hundreds of kilometres. Thus acid rain can fall far from the source of pollution.

When mist or fog droplets condense they will remove pollutants from the air and can become more strongly acid than acid rain. Even snow can be acid. Gases and particles, not dissolved in water, with a low pH can also be deposited directly onto soil, grass and leaves. It is possible that even more acidity is deposited in this way than by rain! Not much is known about this process, and it is particularly difficult to study.

Sulphur dioxide is an acidic which dissolves in water to form sulphurous acidic, H2SO3.In the atmosphere, sulphur dioxide dissolve in water droplets to form sulphurous acidic.

SO2(g) + H2O(l) H2SO3(aq)

1.3.4 Effects of acid rain

* Acid rain can increase the acidity of lakes, dams and streams and cause the death of aquatic life.

* Acid rain can increase the acidity of soil, water and shallow groundwater.

* Acid rain erodes buildings and monuments. Acid particles in the air are suspected of contributing to respiratory problems in people.

Ammonia

2.0 Ammonia

2.1 Uses of ammonia

1. In the manufacture of chemical fertilizers 3. In the making of synthetic fibre and such as ammonium sulphate, ammonia nylon.nitric, ammonia phosphate and urea.

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2. As a degreasing agent in aqueous form to

remove greasy stains in the kitchen.

2.2 The properties of ammonia

Properties Observation/ExplanationPhysical state Colourless gas

Smell Pungent

Effect on the moist red litmus paper Turns red litmus to blue

Solubility in water Very soluble

Reaction between ammonia gas and hydrogen chloride gas

Dense white fumes are formed

2.3 Manufacture of ammonia

1. Ammonia is manufacture on a large scale in industry through the haber process. In this process,

ammonia is formed form direct combination of nitrogen and hydrogen gas in the volume ratio 1:3.

2. The gas nitrogen obtain form the fractional distillation of liquefied air. The hydrogen gas is obtained

form the cracking of petroleum or from the catalysed reaction of natural gas, CH4, with steam.

CH4(g) + H2O(g) CO(g) + 3H2(g)

3.The mixture of nitrogen and hydrogen gases is passed over an iron catalyst under

controlled optimum condition as below to form ammonia gas.

i.Temperature: 450-500°C

ii.Pressure: 200-500 atmospheres

iii.Catalyst used: Iron fillings N2(g) + 3H2(g) 2NH3(g)

4.Under these control optimum condition, only 15% of the gas mixture turn into ammonia gas. The

nitrogen and hydrogen that have not reacted are then flow back over the catalyst again in the reactor

chamber

. 5.The ammonia product is then cooled at a low temperature so that it condenses into a liquid in the cooling chamber.

A flow scheme for the Haber Process looks like this:

2.4 The usage of ammonia in ammonium fertilizers.

2.4.1 Examples of ammonium fertilizers

Ammonia fertilisers are produced from the neutralisation of ammonia with a mineral acid.Ammonia is used to produce fertilisers because it contains nitrogen

The main fertiliser is ammonium nitrate.This is produced by the reaction of ammonia with nitric acid.

nitric acid    +    ammonia        ammonium nitrate.HNO3(aq)    +     NH3(g)                 NH4NO3(aq)

The above reaction is an example of neutralisation,giving a neutral salt (but no water).

Ammonia with sulfuric acid would give ammonium sulphate. (NH4)2SO4(aq) Ammonium nitrate has a higher percentage of nitrogen for the same mass of fertiliser.

2.4.2 The effectiveness of ammonium fertilisers

2.4.3 How to prepare ammonium nitrate by using ammonia and nitric acid