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

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.