Module 4 - Basic concepts of organic chemistry

Question 1

Define aliphatic hydrocarbon

Answer 1

Carbon and hydrogen joined in straight chains, branched chains or non-aromatic rings

Question 2

Define alicyclic hydrocarbon

Answer 2

Aliphatic hydrocarbon arranged in non-aromatic rings with or without side chains

Question 3

Define aromatic hydrocarbon

Answer 3

A compound containing a benzene ring

Question 4

Give three homologous series of aliphatic compounds and their functional group

Answer 4

Alkane - single carbon to carbon bonds
Alkene - at least one double carbon to carbon bonds
Alkyne - at least one triple carbon to carbon bonds

Question 5

Define homologous series

Answer 5

Series of organic compounds with the same functional group but each successive member differing by CH2

Question 6

Define saturated hydrocarbon

Answer 6

Single carbon to carbon bonds only

Question 7

Define unsaturated hydrocarbon

Answer 7

At least one carbon to carbon double bond

Question 8

Give three examples of fossil fuels

Answer 8

Diesel
Petrol
Oil

Question 9

Give two reasons why we are concerned over the use of fossil fuels

Answer 9

Non-renewable so will eventually run out (finite resource)
Release carbon dioxide when complete combustion occurs which contributes to global warming

Question 10

Define biofuel

Answer 10

A fuel immediately from living matter

Question 11

Advantage of biofuels

Answer 11

Plants take in carbon dioxide as they photosynthesise and release the same amount when they burn

Question 12

Disadvantage of biofuels

Answer 12

Land is used to grow plants for fuel instead of food

Question 13

The single covalent bonds in alkanes are called…

Answer 13

Sigma bonds

Question 14

A sigma bond is the result of….

Answer 14

The direct overlap of 2 orbitals

Question 15

Why does boiling point of alkanes increase as chain length increases and branching increases?

Answer 15

Molecules have a larger surface area
More surface contact between molecules
More London forces act between molecules
More energy required to overcome the forces

Question 16

Define hydrocarbon

Answer 16

A compound containing only hydrogen and carbon

Question 17

General formula of alkanes:

Answer 17

CnH2n+2

Question 18

Products of complete combustion of alkanes

Answer 18

Carbon dioxide
Water

Question 19

Products of incomplete combustion of alkanes

Answer 19

Carbon monoxide
Water

Question 20

Why is incomplete combustion harmful?

Answer 20

Carbon monoxide is toxic

Question 21

How is the issue of incomplete combustion solved in modern cars?

Answer 21

Catalytic converter into the exhaust system

Question 22

The condition and mechanisms for the halogenation of alkanes

Answer 22

U.V light / bright sunlight
Free radical substitution

Question 23

Describe the mechanism of homolytic fission

Answer 23

Covalent bond breaks
One electron goes to each group
Forms free radicals

Question 24

Describe the mechanism of heterolytic fission

Answer 24

Covalent bond breaks
Both electrons go to the same group
Forms ions

Question 25

Three stages of free radical substitution

Answer 25

Initiation
Propagation
Termination

Question 26

Define fuel

Answer 26

Source of energy

Question 27

Give the name of the shape and the bond angle around the C in a carbon to carbon double bond

Answer 27

Trigonal Planar
Bond angle = 120

Question 28

Define orbital

Answer 28

A region of space where electrons are most likely to be found

Question 29

What forms a pi bond in alkenes?

Answer 29

Sideways overlap of 2 p orbitals

Question 30

Define structural isomer

Answer 30

Compounds with the same molecular formula but a different structural formula

Question 31

Define stereoisomer

Answer 31

Compounds with the same structural formula but a different arrangement of atoms in space

Question 32

The type of stereoisomerism shown by alkenes is…

Answer 32

E/Z isomerism