chem paper 2 mistakes

what is the order of priority when naming molecules?

carboxylic acids >aldehydes>ketones>alcohols>alkenes>halogenoalkanes

what intermolecular forces are in aldehydes and ketones?

dipole-dipole (C=O)

two ways of maximising the yield of a compound obtained by distillation of a mixture?

keep the temperature of the reaction mixture below the boiling point of the other compounds in the mixture

cool the collecting vessel

when dehydrating an alcohol to make an alkene w/ H2SO4, what is used as the electrophile?

H+ from the H2SO4

attracted to the lone pair on O in the OH

used to undergo elimination

how does E/Z stereoisomerism arise?

C=C bond cannot rotate and

each carbon in the double bond has 2 different groups attached.

bonding and shape of a benzene molecule?

each C has three covalent bonds

the spare electrons in a p orbital overlap

forming a pi cloud of delocalisation

6C ring in a planar shape, 120 BA

C–C bonds equal in length

stability of benzene vs that of the hypothetical cyclohexa-1,3,5-triene molecule?

the expected enthalpy of hydrogenation of theoretical is –360 kJ mol–1

that of benzene is less exothermic by 152 kJ mol–1

benzene is more stable

what would be a suitable enthalpy of hydrogenation for cyclohexa-1,3-diene, as it is not exactly double that of cyclohexene?

–239 to –121

alternating double bonds

allows some delocalisation/overlap of p orbitals

equation to form electrophile for F-C acylation?

CH3CH2COCL + AlCl3 → AlCl4- + C⁺OCH2CH3

what is removed when acyl chloride and alcohol react via nucleo/add slim to form an ester?

HCl

propylamine reaction in water and colour change when universal indicator added?

CH3CH2CH2NH2 + H2O ⇌ CH3CH2CH2NH3+ + OH–

green turns blue

why is an aqueous solution is obtained when nitrobenzene is reduced into phenyl amine even though phenylamine is insoluble in water?

C6H5NH2 is present as ionic salt

glycerol structure?

propane-1,2,3-triol

what is a suitable reagent for the hydrolysis of a protein in TLC?

concentrated HCl to hydrolyse the peptide bond/amide link O=CNH

how may two functional group isomers with the same relative atomic mass be differentiated between via high res mass spec using electrospray ionisation?

their precise relative molecular masses will be different

meaning of the term complementary when it is used to refer to DNA strands?

must have base sequences that match

AT GC

explain how carbon dioxide causes global warming

C=O absorbs IR radiation

collisions between molecules transfer the radiation warming the atmosphere

how does shaking distillate from reflux with saturated NaCl solution allow the desired product to be separated using separating funnel?

the liquids are immiscible/dont mix

how can you tell if a cloudy liquid has been dried by a drying agent?

will go clear

why does NaBH4 reduce aldehydes but not alkenes?

the H^- ion is attracted to partially positive C in aldehydes

but in alkenes the C=C is electron rich

so it repels the ion and can only be attacked by electrophiles

why does presence of Cl make a carboxylic acid stronger?

electron withdrawing/has (-) inductive effect

so weakens the O-H bond

or makes COO- less negative/more stable so less likely to accept H+

why would using a conical flask instead of a beaker give more accurate results in an experiment?

reduces loss of liquid droplets

conditions for fehlings test and colour change?

warm in water bath

blue to red colour change due to red ppt formation