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A2 Chemistry Chapter 1. Chapter 1 Objectives. Reactions of halogenoalkanes. Isomers. Reactions of Alkenes. Electrophilic addition. Optical isomers. Nucleophilic addition. Reactions of Alcohols. A2: Chains and Rings Revisited Chapter 1 Objectives.
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A2 ChemistryChapter 1 Chapter 1 Objectives Reactions of halogenoalkanes Isomers Reactions of Alkenes Electrophilic addition Optical isomers Nucleophilic addition Reactions of Alcohols
A2: Chains and Rings RevisitedChapter 1 Objectives • Describe and explain structural isomerism in compounds with the same molecular formula but different structural formula. • Describe and explain cis-trans isomerism in alkenes, in terms of restricted rotation about a double bond. • Determine the possible structural and/or cis-trans isomers of an organic molecule of given molecular formula. • Describe and explain optical isomerism arising from molecules with a chiral centre. • Recall from Chemistry 1, the chemical reactions of alkanes, alkenes, alcohols and halogenoalkanes. • Show knowledge and understanding of the following reaction mechanisms: free radical, substitution, electrophilic addition, nucleophilic addition • Nomenclature should follow IUPAC rules for naming of organic compounds. For example, 3 methylpentane for CH3CH2CH(CH3)CH2CH3.
Draw and name all possible isomers for the molecular formula: C4H8O2 Butanoic acid 2-hydroxy butanal 4-hydroxy butan-2-one 2-hydroxy butan-2-one 1-hydroxy butan-2-one 2-methyl propanoic acid 3-hydroxy butanal 2-methyly,2-hydroxy propanal 4-hydroxy butanal
Electrophilic addition HBr to any C=C double bond
Nucleophilic substitution Nucleophile to any C-Br bond
Reactions of Alcohols CH3CH2Br CH2=CH2 + H2O Bromoethane Ethene • Dehydration with hot Al2O3 • HBr in situ with conc H2SO4 + NaBr • Reflux with: • Excess Sulphuric acid • dichromate • Distil with: • Sulphuric acid • dichromate CH3CH2OH CO2 + H2O CH3CHO CH3COOH Ethanal combustion Ethanoic acid ethanol • Ethanoic acid • H+ catalyst • reflux Na metal CH3COOCH2CH3 + H2O CH3CH2O-Na+ + H2 Ethyl ethanoate Sodium Ethoxide Name? Products?
Reactions of Halogenoalkanes CH3CH2OH CH3 CH2 NH2 ethanol Ethylamine • Excess alcoholic ammonia under pressure • Hydrolysis: OH-(aq) or H2O CH3CH2Br bromoethane Products? Name? • Hot ethanolic NaOH CH2=CH2 Ethene
Reactions of Alkenes (ethene) CH3CH3 Ethane H2(g) + Ni catalyst CH2=CH2 Addition polymerisation CH2BrCH2Br -(-CH2-CH2-)-n + Br2 ethene 1,2-dibromoethane Polythene H2O(g) + phosphoric acid catalyst + HBr Name? Products? CH3CH2Br CH3CH2OH bromoethane Ethanol
Optical Isomers One form produces the flavours of spearmint and the other the flavours of caraway. Chiral centre Carvone Use the molymod kits to build a representation of carvone.