AQA Unit 2: Chemistry in Action

Revision notes from the second half of the AS chemistry course including:

  • Energetics
  • Kinetics
  • Equilibria
  • Redox Reactions
  • Group 7, the Halogens
  • Group 2, the Alkaline Earth Metals
  • The Extraction of Metals
  • Haloalkanes
  • Alkenes
  • Alcohols
  • Analytical Techniques
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Table of Contents
Endothermic and exothermic reactions4
Measuring enthalpy changes4
Hess' law5
Enthalpy changes of combustion6
Representing thermochemical cycles6
Bond enthalpies7
Collision theory9
The Maxwell-Boltzmann distribution9
The idea of equilibrium13
Changing the conditions of an equilibrium reaction13
Equilibrium reactions in industry13

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Elimination reactions in haloalkanes30
The formation of haloalkanes30
Reactions of alkenes34
Polymerisation of alkenes36
Alcohols- introduction38
Ethanol production38
The reactions of alcohols38
Analytical techniques40
Mass spectrometry41
Infra-red spectroscopy41
Glossary of Terms42

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Endothermic and Exothermic Reactions
Chemical reactions involve energy transfers associated with:
i) The breaking of bonds (heat taken in).
ii) The making of bonds (heat given out).
The energy change is normally in the form of heat change.
Enthalpy changes can be:
i) Exothermic:
a) Heat given…

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In experiments to find enthalpy changes:
i) A known mass, m, of liquid (normally water) is used to absorb the heat from the
ii) The temperature change, T, is measured.
iii) Constant stirring gives an even distribution of heat.
Enthalpy change is: mcT

Enthalpy of Neutralisation:…

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Hess' law simply means H1=H2+H3.

Enthalpy Changes of Combustion, Hc
This is the energy given out when one mole of a substance is burned completely in oxygen at
100kPa and 298K.
Combustion is always exothermic.
Note that the enthalpy change of formation of CO2 and the enthalpy…

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