Chemistry, Third edition

346 18 · COMMON CLASSES OF ORGANIC COMPOUNDS Benzoic acid In benzoic acid, a carboxyl group is attached to the benzene ring: The ...

SUBSTITUTED BENZENE DERIVATIVES 347 The presence of the aromatic ring makes aniline a much weaker base than ammonia. Aniline is ...

348 18 · COMMON CLASSES OF ORGANIC COMPOUNDS Revision questions 18.1.Write the structural formulae of the following: (i) hexan- ...

REVISION QUESTIONS 349 (v)adrenaline (vi)the polymer Saran (used for kitchen wrap). 18.11.A carbonyl compound X has been found b ...

Separating Mixtures Objectives Describes the techniques used by chemists to separate mixtures Demonstrates how to separate sol ...

SEPARATING A SOLID FROM A LIQUID 351 BOX 19.1 Folding a filter paper The diagrams in Fig. 19.2 show how a filter paper is folded ...

352 19 · SEPARATING MIXTURES Solid dissolved in a liquid (in solution) The solid cannot be separated from the solvent by filteri ...

SEPARATING TWO LIQUIDS 353 BOX 19.2 Recrystallization Recrystallizationis used to purify a product. Many chemical preparations g ...

19 · SEPARATING MIXTURES Miscible liquids Two miscible liquids can be separated by simple distillation (Fig. 19.7) if one liquid ...

SEPARATING SOLIDS Separating solids If a solid sublimes(passes from the solid state directly to the vapour state), this fact can ...

19 · SEPARATING MIXTURES Ammonium chloride is another example of a solid that is saidto sublime, but this is untrue; it actually ...

SOLVENT EXTRACTION replace the ions now bound to the exhausted resin and the column is ready for use again. For example, hard wa ...

358 19 · SEPARATING MIXTURES BOX 19.3 Zeolites Some aluminosilicates are known as zeolites. Zeolites are part of a class of comp ...

SOLVENT EXTRACTION 359 BOX 19.4 Reasoning behind multiple extractions If a compound is shaken in a separating funnel with two im ...

19 · SEPARATING MIXTURES Soxhlet extraction A compound can be isolated from a crude, solid product by repeated extraction using ...

CHROMATOGRAPHY sively in forensic science to detect and identify trace amounts of substances. There are many types of chromatogr ...

19 · SEPARATING MIXTURES column it separates into coloured bands of its components because the components move through the colum ...

CHROMATOGRAPHY 363 Gas chromatography (GC) Gas chromatography (GC) is used for checking the purity or identity of volatile liqui ...

19.1.What technique would you use to separate the following? (i) Solid potassium chloride from an aqueous solution of potassium ...

REVISION QUESTIONS 365 (ii)What technique could you use to separate and collect the dyes? 19.5.Amino acids, which are colourless ...