A-Level Chemistry Edexcel 9CH0

know that optical isomerism is a result of chirality in molecules with a single chiral centre

understand that hydrogen bonding affects the physical properties of carboxylic acids, in relation to their boiling temperatures and solubility

understand that carboxylic acids can be prepared by the oxidation of alcohols or aldehydes, and the hydrolysis of nitriles

understand the reactions of carboxylic acids with:

i) lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether ii) bases to produce salts iii) phosphorus(V) chloride (phosphorus pentachloride) iv) alcohols in the presence of an acid catalyst

be able to identify the acyl chloride and ester functional groups

understand the reactions of acyl chlorides with:

i) water ii) alcohols iii) concentrated ammonia iv) amines

understand the hydrolysis reactions of esters, in acidic and alkaline solution

understand how polyesters are formed by condensation polymerisation reactions

understand that optical isomerism results from chiral centre(s) in a molecule with asymmetric carbon atom(s) and that optical isomers areobject and non-superimposable mirror images

know that optical activity is the ability of a single optical isomer to rotate the plane of polarisation of plane-polarised monochromatic light in molecules containing a single chiral centre

understand the nature of a racemic mixture

be able to use data on optical activity of reactants and products as evidence for S_N1 and S_N2 mechanisms

be able to identify the aldehyde and ketone functional groups

understand that aldehydes and ketones:

i) do not form intermolecular hydrogen bonds and this affects their physical properties ii) can form hydrogen bonds with water and this affects their solubility

understand the reactions of carbonyl compounds with:

i) Fehling’s or Benedict’s solution, Tollens’  reagent and acidified dichromate (VI) ions In equations, the oxidising agent can be represented as O

ii) lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether In equations, the reducing agent can be represented as H

iii) HCN, in the presence of KCN, as a nucleophilic addition reaction, using curly arrows, relevant lone pairs, dipoles and  evidence of optical activity to show the mechanism

iv) 2,4-dinitrophenylhydrazine (2,4-DNPH), as a qualitative test for the presence of a carbonyl group  and to identify a carbonyl compound given data for the melting temperatures of derivatives The equation for this reaction is not required

v) iodine in the presence of alkali

be able to identify the carboxylic acid functional group