isomerism and carbonyl compounds

Question 1

what is a chiral carbon atom

Answer 1

a carbon atom with four different groups attached to it

Question 2

what are enantiomers if they can be super iomposed on each other

Answer 2

achiral and there is no optical isomerism

Question 3

what is an eantiomer

Answer 3

molecule has same structural formula as another
but with four groups arranged around a chiral carbon atom so that is is a non-superimposable mirror image of the other molecule

Question 4

what is an optically active molecule

Answer 4

one that rotates plane polarised light

Question 5

what is a racemate

Answer 5

a mixture that contains equal quantities of each eantiomer of an optically active compound

Question 6

what enantiomers do to plane polarised light

Answer 6

the molecules interact with the light and rotate the place of the vibration of the light
one enantiomer will rotate the light clockwise
the other enantiomer will rotate the light counter clockwise

Question 7

when can the aldehyde group only occur on a chain

Answer 7

an aldehyde group can only occur at the end of a chain

Question 8

what is the shortest ketone and why

Answer 8

the shortest ketone is 3 carbons long as the carbonyl group must be connected to 2 aryl or alkyl R-groups

Question 9

what is aryl

Answer 9

aryl-based on an aromatic system

Question 10

what is alkyl

Answer 10

based on a satuarted hydrocarbon group

Question 11

what is the strongest type of intermolcular force in carbonyl compounds and why?

Answer 11

permenant dipole-dipole forces

as the carbonyl group is strongly polar

Question 12

what is the boiling point of carbonyl compounds compared with other organic compounds

Answer 12

it is higher than alkanes and alkenes as they contain van der waals forces which are weaker than dipole-dipole forces
it is lower than carboxylic acids and alcohols however as they contain hydrogen bonds which are stronger

Question 13

what is the solubility of carbonyl compounds in water like

Answer 13

shorter chain ketones and aldehydes mix perfectly with water and form hydrogen bonds
longer chain ketones and aldehydes do not mix well as the carbonyl compounds are less soluble in water

Question 14

what are the conditions for esterficartion

Answer 14

heat under reflux

with concentrated sulfuric acid

Question 15

what are the conditions for base hydrolysis

Answer 15

heat under reflux

with dilute alkaline

Question 16

what are the conditions for acid hydrolysis

Answer 16

heat under reflux

dilute sulfuric acid catalyst

Question 17

what are the two key differences between acid and base hydrolysis

Answer 17

acid hydrolysis is reversible
base hydrolysis is not
base hydrolysis gives a carboxylate salt
acid hydrolysis gives a carboxylic acid

Question 18

what is acylation

Answer 18

the process by which an acyl group is introduced to another molecule

Question 19

what is saponification

Answer 19

making soap

Question 20

what are the conditions for making biodiseal

Answer 20

triglyceride ester is reacted with methanol

with a strong alkali as a catalyst

Question 21

what are the three factors that can vary the rate at how readily acylation occurs

Answer 21

magnitude of charge on the carbonyl carbon
how easily the leaving group is lost
how good the nucleophile is

Question 22

name three uses of esters

Answer 22

solvents
plasticisers
perfumes

Question 23

what is biodeseal

Answer 23

a mixture of methyl esters of fatty acids which can be used as a carbon neutral fuel

Question 24

what does the reaction of an acyl anhydride with a nucleophile always give

Answer 24

a carboxylic acid

Question 25

what is optical isomerism

Answer 25

a type of stereoisomerism

same structural formula but atoms are arranged differently in space