Topic 12
Nitrogen
and Sulfur
Topic 12 explains why nitrogen is so unreactive (the strong N≡N triple bond and its lack of polarity), the basicity of ammonia and the formation and structure of the ammonium ion, and the displacement of ammonia from its salts (12.1.1, 12.1.2); then the natural and man-made oxides of nitrogen, their catalytic removal in a converter, PAN and photochemical smog, and the direct and catalytic roles of NO and NO₂ in acid rain (12.1.3 to 12.1.5). The sulfur page covers the sources of sulfur dioxide, acid rain and its use as a food preservative.
Revision Notes
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Nitrogen and Ammonia
The unreactivity of nitrogen, the basicity of ammonia, the ammonium ion and the displacement of ammonia from its salts.
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Oxides of Nitrogen and the Environment
The formation and removal of oxides of nitrogen, photochemical smog and PAN, and the role of NO and NO₂ in acid rain.
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Sulfur Dioxide: Acid Rain and Food Preservation
The formation of atmospheric sulfur dioxide, its role in acid rain and its use as a food preservative.
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Nitrogen and Sulfur Map
Cambridge International AS & A Level Chemistry · Topic 12 Nitrogen and sulfur
All of Topic 12 on one A4 page: nitrogen, ammonia and ammonium, oxides of nitrogen, PAN and acid rain.
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12.1.1
12.1.2
- c
describe and explain the displacement of ammonia from ammonium salts by an acid–base reaction
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12.1.3
- c
state and explain the catalytic removal of oxides of nitrogen from the exhaust gases of internal combustion engines
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12.1.4
- 12.1.4
understand that atmospheric oxides of nitrogen (NO and NO2) can react with unburned hydrocarbons to form peroxyacetyl nitrate, PAN, which is a component of photochemical smog
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12.1.5
- b
describe the catalytic role of NO and NO2 in the oxidation of atmospheric sulfur dioxide in the formation of acid rain
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