A-level Chemistry/OCR (Salters)/Colour by Design/Check Your Notes

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Colour By Design!

What you should know!!

  1. Absorption of ultraviolet light and visible light in terms of transitions between electronic energy levels.
  2. Use of ultraviolet (u.v.) and visible spectroscopy to help identify unsaturated organic molecules.
  3. Colour changes associated with the following types of chemical changes: acid-base (indicators), ligand exchange, redox, precipitation and polymorphism (different crystal structures).
  4. The relationship between the properties of pigments (colour shade, colour intensity, fastness) to relevant properties (Storyline CD2 and CD3).
  5. General principles of gas-liquid chromatography (g.l.c.)
  6. Techniques used to identify the materials used in a painting, including the use of g.l.c. atomic emission spectroscopy, visible spectroscopy (reflection and transmission) (Storyline CD3 and CD4; Activities CD4.1 to CD4.5).
  7. Nature of fats and oils as mixed esters of propane-1,2,3-triol with varying degrees of unsaturation.
  8. An outline of the process of oxidative cross-linking by which unsaturated oils harden; the relationship of this process to their use as media in oil-based paints.
  9. What arenes and arene derivatives (aromatic compounds) are.
  10. Structure of benzene.
  11. How the characteristic properties of aromatic compounds arise from the delocalisation of electrons.
  12. Following electrophilic substitution reactions of arenes: halogenation of the ring, nitration, sulphonation, Friedel-Crafts alkylation and Friedel-Crafts acylation.
  13. Formation of azo dyes by coupling reactions involving diazonium compounds.
  14. Structure of a dye molecule in terms of its various components: chromophore, groups which modify the chromophore, groups which made the dye more soluble in water and groups which attach the dye to the fibre (Storyline CD5 to CD7).
  15. Ways in which dyes attach themselves to fabrics: weak intermolecular forces, hydrogen bonds, ionic attractions and covalent bonding (Storyline CD7; Activity CD7.2).
  16. Relationship between the colour of a dye and the presence of a chromophore, and groups that modify the chromophore, in the dye molecule.
  17. Relationship between colour in materials and transitions between electronic energy levels.