C25. Nomenclature and Isomerism (A2)

Question 1

Describe the nomenclature of alkenes.

Answer 1

RCH=CH2
Suffix; -ene

Question 2

Describe the nomenclature of alkynes.

Answer 2

RC≡CH
Suffix; -yne

Question 3

Describe the nomenclature of halogenoalkanes.

Answer 3

R-X
prefix; halo-

Question 4

Describe the nomenclature of carboxylic acids.

Answer 4

RCOOH
Suffix; -oic acid

Question 5

Describe the nomenclature of anhydrides.

Answer 5

RCOOCOR’
Suffix; -anhydride

Question 6

Describe the nomenclature of esters.

Answer 6

RCOOR’
Suffix; -oate (named from parent alcohol and acid)

Question 7

Describe the nomenclature of acyl chlorides.

Answer 7

RCOCl
Suffix; -oyl chloride

Question 8

Describe the nomenclature of amides.

Answer 8

RCONH2
Suffix; -amide

Question 9

Describe the nomenclature of nitriles.

Answer 9

RC≡N
Suffix; -nitrile

Question 10

Describe the nomenclature of aldehydes.

Answer 10

RCHO
Suffix; -al

Question 11

Describe the nomenclature of ketones.

Answer 11

RCOR’
Suffix; -one

Question 12

Describe the nomenclature of alcohols.

Answer 12

ROH
Suffix; -ol
Prefix; hydroxyl-

Question 13

Describe the nomenclature of amines.

Answer 13

RNH2
Suffix; -amine
Prefix; amino-

Question 14

What is a stereoisomer?

Answer 14

Compounds with the same structural formula but a different arrangement of bonds in space; EZ isomer; optical isomer

Question 15

What is an optical isomer?

Answer 15

Compounds that contain an asymmetric carbon that differ in their effect on polarised light; Two non superimposable isomers that are mirror images of each other

Question 16

What is a chiral centre?

Answer 16

Carbon atom that has 4 different atoms or groups of atoms attached

Question 17

What are enantiomers?

Answer 17

Optical isomers that are nonsuperimposable mirror images of each other

Question 18

What is the method of differentiating enantiomers?

Answer 18

Pass light through polaroid, polarises light; Polarised light passed through 2 solutions of same concentration, containing different enantiomers of the same substance; Measure optical rotation with polarimeter; 1 enantiomer will rotate plane of polarisation clockwise, + isomer; Other anticlockwise, - isomer

Question 19

What is a racemate?

Answer 19

Mixture where equal amounts of enantiomers are present in the solution, optically inactive due to enantiomers cancelling each other effects

Question 20

How are only the useful enantiomers formed in nature?

Answer 20

Naturally occurring molecules are formed from enzyme catalyst, forming only one best possible enantiomer

Question 20

What are the options for selling a production 50/50 optical isomers of a drug?

Answer 20

Separate the two isomers, difficult and expensive; Sell the mixture as a drug, wasteful due to half being inactive; Design alternative synthesis of the drug, producing one enantiomer

Question 21

Name an example of a racemate drug that is sold.

Answer 21

Ibuprofen

Question 22

Explain the thalidomide tragedy.

Answer 22

Drug prescribed to relieve morning sickness; Enantiomers were hard to separate, prescribed as racemate; S enantiomer caused birth defects, R enantiomer was a safe sedative