Chemistry , the Acidic Environment Assignment Hsc

Topics: Carbon dioxide, Sulfuric acid, Acid Pages: 8 (2410 words) Published: March 10, 2011
1.Identify the natural sources of sulphur dioxide and oxides of nitrogen.

SO2, natural:
-Geothermal hot springs and volcanic activity are natural sources of SO2. -In the process of decaying of organic matter some bacteria will produces hydrogen sulphide as a waste product which will oxidise, forming so2. -Phytoplankton release dimethyl sulphide (DMS) into the atmosphere, when this is oxidised it forms sulphuric acid.

NOx, natural:
-Lightning activity generates high temperatures to allow oxygen and nitrogen to combine. Nitric oxide combines with oxygen in the presence of lightning. The no will then slowly combine with oxygen in the atmosphere to form no2 -nitrous oxide formed from bacteria on nitrogenous material in soil -bushfires

2.describe, using equations, examples of chemical reactions which release sulphur dioxide and chemical reactions which release oxides of nitrogen

-Combustion of coal containing sulphur
S(s) (in compound) + O2(g) → SO2(g)

-Smelting of sulphide ores (zinc ore)
2ZnS (s) + 3O2 (g) → 2ZnO (s) + 2SO2(g)

-Nitrogen combining with oxygen in the atmosphere
N2(g) + O2(g) → 2NO(g)

-Nitric oxide combining with oxygen in the atmosphere
2NO(g) + O2 (g) → 2NO2(g)

3.Summarise the industrial origins of sulphur dioxide and oxides of nitrogen. Evaluate reasons for concern about their release into the environment.

SO2, industrial:
-Sulphur is contained within most fossil fuels and is released in the form of sulphur dioxide (SO2) during fossil fuel combustion. Some coal or oil reserves contain considerable quantities of sulphur compounds. Most sulphur dioxide (SO2) released into the atmosphere comes from the burning of fossil fuels (mainly coal) in electric power stations, however other uses of fossil fuels also contribute to the pollution, for example... the combustion of petrol or diesel in an engine. . -Smelting of sulphur ores in the extraction of metals process is another industrial means of SO2 pollution, however smelters where metal sulphides are heated in air to remove the sulphur as SO2 are becoming a smaller source of atmospheric SO2 pollution. Most of the SO2 released is now used to make sulphuric acid.

NOx, industrial
-use of nitrogenous fertiliser in agriculture which provides raw material for the bacteria in the soil to feed off and produce dinitrogen oxide -Burning of fossil fuels in transport vehicles (cars, trucks etc) and power stations ( for generation of electricity) Oxides of nitrogen may be present in exhaust fumes emitted into the atmosphere by cars, aeroplanes, trains and boats. Even lawnmowers can emit oxides of nitrogen into the atmosphere -Generating electricity is the largest source of emissions of oxides of nitrogen in Australia. Other industrial sources are mining, oil and gas extraction and different kinds of metal manufacturing and petroleum manufacturing. Effects:

Sulphur dioxide
-irritates the respiratory system and may lead to heart and lung disorders -causes breathing difficulties even at low concentrations
-Unpleasant odour
-causes formation of acid rain

Nitrogen Dioxide
-irritates respiratory tracts
-causes breathing discomfort and encourage heart and lung problems as well as cancer and cell damage. -Sunlight acts on nitrogen dioxide in the presence of hydrocarbons and oxygen to form ozone -NO2 + sunlight → NO + O , then O + O2 → O3

-Ozone aggravates respiratory problems e.g. asthma
-Nitrous oxide (N2O) is a potent greenhouse gas it contributes to global warming, rise in sea level and consequently adverse changes to the biosphere -pollutes atmosphere and increases the chances of the formation of photochemical smog, this may reduce visibility and is a major health hazard -causes the formation of acid rain

4.Assess the evidence which indicates increases in atmospheric concentration of oxides of sulphur and nitrogen Finding evidence for an increase in the...
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