SALTERS ADVANCED CHEMISTRY
"CHECK YOUR NOTES" : THE ATMOSPHERE (1)
Print the list below and tick the box supplied when you have covered the topic in your notes. Most of the points are covered in the Chemical Ideas, with supporting information in the Storyline or Activities. However, if the main source of information is the Storyline or an Activity, this is indicated.
 
1 The gases present in the atmosphere, including some major pollutants, understand values for composition by volume measured in percentage concentration and in parts per million (ppm) (Storyline A1).
2 The idea that rotational, vibrational and electronic energies are quantised.
3 The qualitative changes in rotational, vibrational and electronic energy of molecules caused by the absorption of radiation of appropriate frequency.
4 The relationship between frequency and energy of electromagnetic radiation.
5 The structure and reactivity of ozone and the way it is formed and destroyed in the stratosphere; how ozone acts as a sunscreen (Storyline A3; Activity A3.1),
6 The factors that affect the rate of a chemical reaction and the use of collision theory to explain the effects.
7 The meaning of the terms: enthalpy profile and activation enthalpy.
8 The use of the concept of activation enthalpy to explain the qualitative effect of temperature changes on rate of reaction.
9 The role of catalysts in providing alternative routes of lower activation enthalpy, homogeneous catalysis in terms of the formation of intermediates.
10 The difference between homolytic and heterolytic fission of a covalent bond.
11 The formation, nature and reactivity of radicals; the mechanism of a radical chain-reaction involving initiation, propagation and termination.
12 The reaction of alkanes with halogens (Activities A3.2 and A3.3).
13 The nature and names of halogenoalkanes.
14 The meaning of the terms: hydrolysis, substitution, nucleophile and carbocation.
15 Outline of the preparation of a halogenoalkane from an alcohol, and the principal stages in the purification of an organic liquid product (Activity A4.2).
16 The characteristic properties of halogenoalkanes, comparing fluoro-, chloro-, bromo- and iodo-compounds; boiling points, formation of radicals by interaction with ultraviolet radiation (Storyline A3), and nucleophilic substitution with water, hydroxide ions and ammonia.
17 The mechanism of nucleophilic substitution in halogenoalkanes.
18 The use of relative electronegativity values to predict bond polarity in a covalent bond; the relationship between reactivity of halogenoalkanes and bond enthalpy and bond polarity,
19 The nature and uses of chlorofluorocarbons (CFCs) (Storyline A4) and the relative advantages and disadvantages of replacement compounds (Activity A4.3).
20 The chemical basis of the depletion of ozone in the stratosphere due to halogenoalkanes, involving the formation of halogen atoms and the catalytic role of these atoms in ozone destruction (Storyline A3).
21 The relationship between the 'greenhouse effect' in the troposphere and the absorption characteristics of atmospheric gases (Storyline A6 and A7, Activity A6).
22 A comparison of the different approaches to the control of global warming through the control of carbon dioxide emissions (Storyline A9; Activity A9).
23 The meaning of the term: dynamic equilibrium.
24 The physical and chemical changes occurring when carbon dioxide dissolves in water, and the associated equilibria.
25 The use of Le Chatilier's Principle to explain and predict the effects on the position of equilibrium of changes in concentration, temperature and pressure.