3.3.7 - Optical Isomerism + naming

Question 1

aldehyydes functional group prefix and suffix

Answer 1

. O
||
—- C — H

suffix -al
prefix formyl

Question 2

if 2 aldehyde groups then how is naming different

Answer 2

If two aldehyde groups
then di is put before –al
and an e is added to
the stem.
eg pentanedial

Question 3

ketones func group prefix and suffix

Answer 3

. O
||
—-C—–
suffix* -one
prefix oxo

Question 4

When ketones have 5C’s or more in a chain how is naming different

Answer 4

When ketones have 5C’s or more
in a chain then it needs a number
to show the position of the double
bond. E.g. pentan-2-one

Question 5

if 2 ketone groups how is naming different

Answer 5

If two ketone groups then
di is put before –one and
an e is added to the stem
eg pentanedione

Question 6

prefix oxo should be used for compounds…

Answer 6

The prefix oxo- should be
used for compounds that
contain a ketone group in
addition to a carboxylic acid
or aldehyde
2-oxopropanoic acid

Question 7

carboxylic acid func group and suffix

Answer 7

. O
||
—-C—-OH
suffix -oic acid

Question 8

If there are carboxylic acid groups on both ends of the
chain then it is called a …

Answer 8

dioic acid with an e after stem eg ethanedioic acid

Question 9

nitriles func group, suffix and prefix

Answer 9

—C triple bond N
suffix -nitrile
prefix cyano

Question 10

how to name nitrile w 4 carbons

Answer 10

butanenitrile
C from CN is included in the name

Question 11

amines func group, suffix and prefix

Answer 11

. |
|
—–C—-NH2
|
|
suffix* - -yl - amine
prefix amino

Question 12

2 ways of naming amine w 3 carbons for example

Answer 12

The exam board tend to use the common
version where the name stem ends in -yl
propylamine.
Another version of the same chemical is
propan-1-amine. (

Question 13

when is the prefix amino used when naming amines

Answer 13

If there is another priority
functional group as well
as the amine group then
the prefix amino is used.

. H2N O
\ //
CH—C
/ \
H3C O - H

2-aminopropanoic acid.

Question 14

if amine is secondary how is naming different

Answer 14

If the amine is secondary and has two alkyl
groups attached to the nitrogen, then each chain
is named and the smaller alkyl group is preceded
by an –N which plays the same role as a number
in positioning a side alkyl chain
eg
CH3CH2CH2NHCH3 N-methylpropylamine (common name)
N-methylpropan-1-amine (other name)

Question 15

if amine is tertiary how is naming different

Answer 15

If a tertiary amine similar rules apply, and
each alkyl side group is given an N
eg CH3CH2CH2 -N- CH3
|
CH3

Question 16

if 2 amine groups how is naming different

Answer 16

diamine is suffix
eg hexane-1,6-diamine

Question 17

esters func group, suffix and prefix + example

Answer 17

. ||
—C—O—-
-yl –oate
methyl ethanoate

Question 18

Esters have two parts to their names
The bit ending in –yl comes from the _______ that has formed it and is
next to the single bonded ________. The bit ending in –anoate comes
from the _______. (This is the chain including the C=O bond)

Answer 18

Esters have two parts to their names
The bit ending in –yl comes from the alcohol that has formed it and is
next to the single bonded oxygen The bit ending in –anoate comes
from the carboxylic acid. (This is the chain including the C=O bond)

Question 19

acyl chloride func group suffix and example

Answer 19

. O
//
— C -oyl chloride
\
Cl eg ethanoylchloride

Question 20

amide func group, suffix and example

Answer 20

. O
//
— C -amide
\
NH2 ethanamide

Question 21

how are secondary and tertiary amides named differently

Answer 21

Secondary and tertiary amides
are named differently to show the two (or three) carbon chains.
The smaller alkyl group is
preceded by an –N which plays the same role as a number in positioning a side alkyl chain

Question 22

name this
O
||
H3C—CH2—C—NH—CH3

Answer 22

N-methylpropanamide

Question 23

name this

                  O  CH3
                  ||   | H3C---CH2---C---N---CH3

Answer 23

N,N-dimethylpropanamide

Question 24

acid anhydrides func group, suffix and example

Answer 24

. O
//
R — C
\
O
/
R — C

O
-oic anhydride
Ethanoic anhydride

Question 25

why is ethanoic anhydride named the way it is

Answer 25

It is ethanoic
because it is two ethanoate
groups joined together.
. O
//
CH3–C
\
O
/
CH3 – C

O

Question 26

if the alkyl groups are different how is the acid anhydride named

Answer 26

If the alkyl groups are of
different lengths then
each one is named
e.g. ethanoic propanoic
anhydride
. O
//
CH3– C
\
O
/
CH3–CH2 – C

O

Question 27

order of priority when multiple func groups

Answer 27

Carboxylic acids >carboxylic acid derivative>nitriles>aldehydes>ketones>alcohols>amines>alkenes>halogenoalkanes

Question 28

when compounds have more than one func group ______ priority takes _____ with all others taking _____ form

Answer 28

when compounds have more than one func group highest priority takes suffix with all others taking prefix form

Question 29

structural isomers def

Answer 29

same molecular formula different
structures (or structural formulae)

Question 30

Structural isomerism can arise from

Answer 30

*Chain isomerism
*Position isomerism
*Functional group isomerism

Question 31

what kind of isomers would aldehydes and ketones be classed as

Answer 31

functional group isomers

Question 32

define stereoisomerism

Answer 32

stereoisomers have the same structural formula with different arrangment of atoms

Question 33

2 types of steroisomerism

Answer 33

e-z isomerism
optical isomerism

Question 34

optical isomerism is a type of of stereoisomerism where….

Answer 34

optical isomerism is a type of of stereoisomerism where molecules have the same molecular formula but a different spatial arrangment of atoms in space

Question 35

optical isomerism occurs in …

Answer 35

Optical isomerism occurs in carbon compounds with 4
different groups of atoms attached to a carbon (called
an asymmetric carbon).

Question 36

what is a chiral carbon

Answer 36

A carbon atom that has
four different groups
attached is called a chiral
(asymmetric) carbon
atom

Question 37

4 groups are arranged _____ around carbon atom

Answer 37

These four groups are arranged
tetrahedrally around the carbon.

Question 38

presense of chiral centre leads to the presense of 2 ….

Answer 38

presense of chiral centre leads to the presense of 2 possible isomers that are mirror images of eachother (optical isomers)

Question 39

An ________ carbon atom is _________ and gives rise to ______ ______ (________), which exist as ___ ______ __________ mirror images and differ in their effect on _______ ________ _____. A mixture of ________ amounts of enantiomers is called a ______ _______ (racemate).

Answer 39

An asymmetric carbon atom is chiral and gives rise to optical isomers(enantiomers), which exist as non super-imposable mirror images and differ in their effect on plane polarised light. A mixture of equal amounts of enantiomers is called a racemic mixture (racemate).

Question 40

Two compounds that are optical isomers of
each other are called…

Answer 40

enantiomers

Question 41

Optical isomers have similar …..

Answer 41

physical and chemical properties

Question 42

enantiomers are unique due to their effect…

Answer 42

enantiomers are unique due to thier effect on plane polarised light. each entantiomers causes the rotation of plane polarised lightby 90 degrees in opposite diretions

Question 43

enantiomers exist as

Answer 43

non super-imposable mirror images and differ in their effect on plane polarised light

Question 44

what is a racemate/racemic mixture ?

Answer 44

A mixture containing a 50/50 mixture of the
two isomers (enantiomers) is described as
being a racemate or racemic mixture.

Question 45

how is a racemate formed

Answer 45

A racemate will be formed in a reaction
mechanism when a reactant or intermediate
has a trigonal planar group in the molecule
is approached from both sides by an attacking
species

Question 46

why does a racemate form

Answer 46

There is an equal chance of
either enantiomer forming so
a racemate forms. No
optical activity is seen