Topic 5.5 Organic chemistry IV

Return to AS and A2 chemistry

Questions set on this topic may require the application of knowledge covered in topics 2.2, 4.5 and 5.3.  This topic is considered to contain material of a synoptic nature.

5.5a Organic analysis
Students should be able to:
(i) describe practical tests or combinations of tests to confirm the presence of the following functional groups:

· students will be expected to describe tests to distinguish between primary, secondary and tertiary alcohols
· the halide group may be identified by simple alkaline hydrolysis, subsequent acidification and testing with aqueous silver nitrate
· other groups may be identified by reactions of the student’s choice, but the reactions of the common reagents bromine solution, phosphorus pentachloride, 2,4- dinitrophenylhydrazine solution, Fehling’s solution and ammoniacal silver nitrate, sodium or potassium hydrogencarbonate, iodine in the presence of alkali (or potassium iodide and sodium chlorate(I)) solution, will be expected to be known
(ii) interpret physical data and chemical information, including information relating to derivatives where appropriate, to arrive at the structural formula of a compound
(iii) interpret simple fragmentation patterns from a mass spectrometer
(b) interpret simple infra-red spectra
(c) interpret simple low-resolution nuclear magnetic resonance spectra
· limited to proton magnetic resonance
(d) interpret simple ultra-violet/visible spectra.
· students will not be expected to describe the theory of or the apparatus connected with the production of uv – visible, infra-red or nuclear magnetic resonance spectra
· students will be given tables of data as appropriate.
· students will not be expected to recall specific spectral patterns and/or wave numbers, but may be required to inspect given spectra and tables of data to draw conclusions

5.5b Organic synthesis
Students should be able to:
(i) propose practicable pathways for the synthesis of organic molecules
(ii) propose suitable apparatus, conditions and safety precautions for carrying out organic syntheses, given suitable information
(iii) demonstrate familiarity with a range of practical techniques used in organic chemistry
· mixing, boiling under reflux, fractional distillation, filtration under reduced pressure (filter pump and Buchner funnel), recrystallisation, determination of melting temperature and boiling temperature, and heating with a variety of sources, whilst having a regard for safety, typify some of these practical techniques. When considering aspects of laboratory safety students will be expected to relate these to the specific hazards of the reaction or chemicals being handled.
· it will be assumed that students wear eye protection during all practical work
(iv) demonstrate an understanding of the principles of fractional distillation in terms of the graphs of boiling point against composition.
· students will not be expected to recall experimental procedures for obtaining graphs of boiling point against composition
· knowledge of systems that form azeotropes will not be expected

5.5c Applied organic chemistry
Students should be able to appreciate the importance of organic compounds in pharmaceuticals, agricultural products and materials. Questions will be confined to the following aspects:
(i) changes to the relative lipid/water solubility of pharmaceuticals by the introduction of non-polar side-chains or ionic groups
(ii) the use of organic compounds such as urea as sources of nitrogen in agriculture and their advantages as compared with inorganic compounds containing nitrogen
(iii) the use of esters, oils and fats
· to include flavourings, margarine, soaps and essential oils
· oils and fats to be considered from the viewpoint of saturation
(iv) properties and uses of addition polymers of ethene, propene, chloroethene, tetrafluoroethene and phenylethene, and of the condensation polymers (polyesters and polyamides).
· this should include consideration of the difficulties concerned with the disposal of polymers
· no specific reactions will be the subject of recall questions. Students will be expected to give some examples of compounds and reactions to illustrate their answers.