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WHy does something not become a steroisomer
Does not contain a chiral centre OR does not contain C attached to 4 different groups OR contains two identical/ethyl groups OR symmetrical (product)
Describe two ways the result would show that the product is impure.
M2 Lower (than data book value) M3 Melts over a (wide) range of temperature (rather than sharp/narrow range if pure)
Describe the recrystallisation process used to purify the aspirin. Include the method and apparatus used.
M1 Dissolve crude product in hot solvent (water and ethanol) M2 of minimum volume M3 Filter (hot to remove insoluble impurities) M4 Cool (to recrystallise) M5 Filter under reduced pressure / with Buchner/Hirsch apparatus M6 Wash (with cold solvent) and dry
State how the value calculated in part (b) is likely to differ from data book values. Give one reason, other than heat loss, for this difference.
M1 Less exothermic Allow Less negative (value) / Lower M2 Incomplete combustion
An electrophile is:
A species that accepts a lone pair of electrons to form a covalent bond.
Amine A is formed in step 2 and amine B is formed in step 5. Explain why the yield of B in step 5 is less than the yield of A in step 2.
In Step 5 further substitution / gives other amine products 1 In Step 2 only one amine
A nucleophile is
A species that donates a lone pair of electrons to form a covalent bond.
WHy is a lid required in chormatogrpahy
M1 lid/cover (on beaker) Then any 2 from these 3 * prevents escape of vapour (from beaker) / evaporation of solvent (from beaker) * so atmosphere in beaker is saturated with solvent vapour owtte * to reduce evaporation from the plate
State why the amino acids separate on the TLC plate.
Difference in the balance between solubility in solvent/mobile phase and attraction to/retention on stationary phase