(6) Isomerism

Question 1

what is isomerism and two types

Answer 1

same molecular but different arrangement of atoms; structural and stereoisomerism

Question 2

what is structural isomerism and the three types

Answer 2

atoms bonded in a different order; functional group, positional and chain isomerism

Question 3

what is functional group isomerism

Answer 3

same molecular formula but atoms are arranged to change functional group

Question 4

what is positional isomerism

Answer 4

same molecular formula and functional group. Functional group has moved to a different position on carbon chain.

Question 5

what is chain isomerism

Answer 5

same molecular formula but different arrangement of carbon skeleton

Question 6

what is stereoisomerism and the two types

Answer 6

atoms bonded in the same order but arranged differently in space, geometric and optical isomerism

Question 7

what is geometric isomerism

Answer 7

restricted rotation (often involving C=C) and two different groups on the left hand of the bond and two different groups on the right hand of the bond

Question 8

what is optical isomerism

Answer 8

two compounds that contain the same connectivity and different spacial arrangements of the atoms but have non-superimposable mirror images EG: lactic acid

Question 9

ketone

Answer 9

. O
II
R-C-R

Question 10

aldehyde

Answer 10

. O
II
R-C-H

Question 11

carboxylic acid

Answer 11

. O
II
R-C-OH

Question 12

what are two optical isomers called

Answer 12

enantiomers

Question 13

what does optically active mean

Answer 13

substances that can rotate the plane of the plane-polarised light

Question 14

what is plane-polarised light

Answer 14

light that has been passed through a polarising filter. The waves all travel in the same plane so the plane can be rotated from left to right (due to spatial arrangement of the atoms)

Question 15

what are the types of optical isomers

Answer 15

d-isomer (rotates plane to the right) and I-isomer (rotates plane to the left)

Question 16

what is a chiral (asymmetric chiral centre)

Answer 16

an atom with 4 different atoms or groups of atoms attached to it. (identified using *)

Question 17

what is achrial

Answer 17

a molecule without a chiral centre and it is optically inactive (cannot rotate plane)

Question 18

what is chirality

Answer 18

one of the isomers is non-superimposable mirror image of the other

Question 19

what is a racemic mixture

Answer 19

a mixture of optical isomers which contain equal numbers of moles of each of the d-isomers and i-isomers; there is no overall effect on the plane rotation

Question 20

what is stereospecificity due to

Answer 20

the stereospecific nature of the receptor sites to which the drugs bind

Question 21

how are receptor sites stereospecific

Answer 21

due to the functional groups that are present in the site. they can only interact with one of the optical isomers bc of the position of the groups/ isomer may not fit into the active site

Question 22

why would racemic mixtures such as isoflurane not be separated

Answer 22

there are no harmful/ unwanted effects from the other optical isomer and would be more expensive to separate them