Module 4 Core Organic Chemistry

Question 1

Define homologous series

Answer 1

Molecules with the same functional group but each successive member differs by CH2

Question 2

What is molecular formula

Answer 2

Number of atoms of each element in a compound e.g C4H8

Question 3

What is displayed formula

Answer 3

Shows the (drawn) position of atoms and bond between them

Question 4

What is skeletal formula

Answer 4

The simplified organic formula which only showed the carbon skeletal and atoms of the function groups

Question 5

What is the structural formula

Answer 5

A representation which shows the atoms in a molecule carbon by carbon with attached hydrogens and functional groups

Question 6

What is empirical formula

Answer 6

Simplest whole number ratio of atoms of each element in a compound

Question 7

What is general formula

Answer 7

The simplest algebraic formula of a member of a homologous series

Question 8

What is an isomer

Answer 8

Has the same molecular formula but different structural formula

Question 9

How do you name an alkene

Answer 9

Remove ‘ane’ and add ‘ene’

Question 10

How do you name an alcohol

Answer 10

Remove the ‘e’ and add ‘ol’

Question 11

How do you name a carboxylic acid

Answer 11

Remove ‘e’ and add ‘oic acid’ on the end

Question 12

How do you name a ketone

Answer 12

Remove ‘e’ and add ‘one’ on the end

Question 13

How do you name an aldehyde

Answer 13

Remove ‘e’ and add ‘al’ at the end

Question 14

How do you name a halogenoalkane

Answer 14

Name the halo at the start

Question 15

What is the functional group of an alcohol

Answer 15

OH

Question 16

What is the functional group of a carboxylic acid

Answer 16

COOH (one of the Os is a double bond)

Question 17

What is the functional group of an alkene

Answer 17

Double bond between carbon

Question 18

What is the functional group of an aldehyde

Answer 18

CHO (single bond to H and double bond to O)

Question 19

What is the functional group of a ketone

Answer 19

Double bond to an oxygen in the middle of the chain

Question 20

What is an aromatic compound

Answer 20

Contains a benzene ring

Question 21

What is an aliphatic compound

Answer 21

Contains straight or branched cyclic hydrocarbons but not aromatic

Question 22

What is an alicyclic compound

Answer 22

An aliphatic compound with a ring that isn’t benzene

Question 23

How do you name a branched molecule

Answer 23

1 carbon = methyl
2 carbons = ethyl
3 carbons = propyl

Question 24

Define functional group

Answer 24

A group of atoms in a molecule that is responsible for characteristic properties

Question 25

What are the 3 types of structural isomers

Answer 25

Chain Positional Functional group

Question 26

What is a chain isomer

Answer 26

Same molecular formula but a different carbon chain length

Question 27

What is a positional isomer

Answer 27

The same molecular formula but functional group in a different position

Question 28

What is a functional group isomer

Answer 28

Same molecular formula but different functional group e.g propanal becoming propanone

Question 29

Define saturated

Answer 29

A single bond between carbon atoms

Question 30

Define unsaturated

Answer 30

Has a double bond between carbon atoms

Question 31

What shape do alkanes have

Answer 31

Tetrahedral shape

Question 32

What bond angle do alkanes have

Answer 32

109.5

Question 33

What is a sigma bond

Answer 33

A single covalent bond

Question 34

How is a sigma bond formed

Answer 34

Direct head overlap of atomic orbitals between atoms

Question 35

Define boiling point

Answer 35

Energy needed to turn from a liquid to a gas

Question 36

Which bonds are broken when something reaches its boiling point

Answer 36

Intermolecular forces

Question 37

Describe the trend in boiling points as carbon chain length increases

Answer 37

Boiling point increases More/stronger intermolecular forces More points of contact between molecules More energy needed to break

Question 38

What effect does branching have on boiling point

Answer 38

Increase branching decreases the boiling point Fewer points of contact so less/weaker intermolecular forces Less energy to break

Question 39

Describe the formation of a London dispersion force

Answer 39

At an instant there is an uneven distribution of electrons in the atom/molecule This forms and instantaneous dipole moment due to asymmetry This induces a dipole in a neighbouring atom/ molecule. Attraction between molecules due to opposite dipoles

Question 40

Suggest why the boiling point of halogen molecules increases down group 7

Answer 40

Further down group = more electrons Greater/stronger instantaneous dipole Induces greater/stronger dipole Greater difference in dipoles so stronger attraction More energy needed to break molecules apart