PL

Question 1

carboxylic acids (and phenols) are strong enough acids to

Answer 1

react with strong bases to form salts

Question 2

carboxylic acids reaction with carbonates

Answer 2

react to form water and CO2 in an acid-base reaction

Question 3

redox reactions with carboxylic acids, phenols and alcohols

Answer 3

form salts with metals

Question 4

polyesters

Answer 4

diols and dicarboxylic acids can be made into condensation polymers called polyesters

Question 5

amines

Answer 5

have functional group NH2

strong smell of decaying fish

Question 6

primary amines

Answer 6

have just one alkyl group

Question 7

diamines

Answer 7

have two NH2 groups whichallow them to form condensation polymers

Question 8

properties of amines

Answer 8

1. lone pair on N is responsible for solubility in water and ability to act as bases
2. can form H bonds with water molecules
3. amines with larger alkyl groups are less soluble in water because they are unable to break the H bonds between water molecules
4. lone pair can accept a proton from water to form a dative covalent bond - OH remains in solution so solutions of amines are alkaline
5. react with acidic solutions by accepting a proton, solution will lose strong amine smell

Question 9

primary amides

Answer 9

derivatives of carboxylic acids with the OH groups replaced by NH2

Question 10

carboxylic acids reaction with ammonia

Answer 10

DOES NOT REACT

Question 11

acyl chloride + ammonia&raquo_space;

Answer 11

produces primary amide and HCl

Question 12

secondary amides

Answer 12

H atom in NH2 group of a primary amide replaced with an R (alkyl) group

Question 13

formation of secondary amides

Answer 13

primary amide + acyl chloride&raquo_space; secondary amide + HCl

Question 14

polyamides

Answer 14

aka nylons
diamines and dicarboxylic acids can react together to form polymer chains in polymerisation reactions
monomer units are linked together by secondary amide groups

Question 15

alternative method of producing nylons

Answer 15

using diamine and dicarboxylic acid is slow
therefore, acyl chloride derivative of carboxylic acid is sometimes used
eg. decanoic acid&raquo_space; decandioyl chloride

Question 16

nylon using just one monomer

Answer 16

monomer must contain both a carboxylic acid group and an amine group

Question 17

hydrolysis of esters

Answer 17

usually slow process but can be spread up by H2SO4 catalyst

requires water, produces alcohol and carbpxylic acid

Question 18

alkali hydrolysis of esters

Answer 18

NaOH can be used to hydrolyse esters

ester reacts with hydroxie ion to produce alcohol and carboxylate salt

Question 19

acid hydrolysis of primary amides

Answer 19

RCONH2 + H2O + H+&raquo_space; RCOOH + NH4+

strong acid catalyst

Question 20

acid hydrolysis of secondary amide

Answer 20

RCONHR’ + H2O + H+&raquo_space; RCOOH + R’NH3+

strong acid catalyst

Question 21

alkali hydrolysis of primary amides

Answer 21

RCONH2 + OH-&raquo_space; RCOO- + NH3

uses sodium hydroxide

Question 22

alkali hydrolysis of secondary amides

Answer 22

RCONHR’ + OH-&raquo_space; RCOO- + R’NH2

Question 23

optical isomerism of amino acids

Answer 23

due to presence of 4 different groups on central carbon atom

chirality and enantiomers

Question 24

chiral centre

Answer 24

the carbon atom in an amino acid which is bonded to 4 different groups
the 4 groups can be bonded in different ways

Question 25

enantiomers

Answer 25

mirror images of each other
BUT non-superimposable (not identical)
bonds must be broken to make them identical

Question 26

amino acids in alkaline conditions

Answer 26

carboxyl group loses a proton

Question 27

amino acids in acidic conditions

Answer 27

amine group accepts a proton

Question 28

amino acids in neutral solutions

Answer 28

form zwitterions (act as buffers)
carboxyl group is deprotonated and amine group is protonated

Question 29

maintaining tertiary structure of proteins

Answer 29

id-id bonds between non-polar side chains on amino acids
hydrogen bonds between polar side chains
ionic bonds between ionisable side chains
covalent bonds between -SH groups to form disulphide bridges

Question 30

enzymes

Answer 30

biological catalysts
lower activation enthalpy
(show higher specificity than inorganic catalysts)

Question 31

bonds between enzymes and substrates

Answer 31

have to be weak so that th binding can readily be reversed to release product

usually H bonds or interactions between ionic groups

binding of substrate to enzyme may cause other bonds to weaken within the substrate