Module 4 Organic Chemistry Chapter 11/12

Question 1

What is meant by the term homologous series?

Answer 1

Homologous series is the same functional group with each successive member differing by CH2.

Question 2

State the general formula of cycloalkanes

Answer 2

CnH2n

Question 3

The C-C-C bond angles in cyclohexane are 109.5 degrees.

State and explain the shape around each carbon atom in cyclohexane.

Answer 3

Shape - Tetrahedral

Explanation - Four bonds repel

Question 4

Explain what is meant by the term stereoisomers

Answer 4

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

Question 5

The initiation step involves homolytic fission

Explain why the initiation step is an example of homolytic fission

Answer 5

The breaking of the bond and one electron from the bond pair goes to each atom.

Question 6

What is meant by the term structural isomers?

Answer 6

Compounds/Molecules have the same molecular formula but different structural formula.

Question 7

What is the general formula of alkyl groups

Answer 7

CnH2n+1

Question 8

Suggest one advantage of adding cyclohexane to hexane in petrol

Answer 8

Cyclohexane will burn more efficiently

Question 9

What does a curly arrow represent in mechanisms

Answer 9

Movement of an electron pair

Question 10

What is meant by the term nucleophile

Answer 10

Electron pair donor

Question 11

Describe how a σ-bond forms.

Answer 11

Overlap of orbitals direct.y between the bonding atoms

Question 12

Describe two other ways in which waste poly(propene) can be processed in a sustainable way

Answer 12

Combustion for energy production

Use as an organic feedstock

Question 13

Describe one difference between the σ bond and the π bond

Answer 13

σ bond has direct/head-on overlap of orbitals and π bond has sideways overlap

Question 14

What reagents and conditions are needed to convert alkenes into saturated hydrocarbon

Answer 14

Hydrogen and nickel catalyst

Question 15

At room temperature and pressure the first four members of the alkanes are all gases but the first four alcohols are all liquids .
Explain this difference in terms of intermolecular forces

Answer 15

Alcohols have hydrogen bonds and Van Der Waals Forces

Hydrogen bonds are stronger than Van Der Waals forces in alkanes

Question 16

Suggest the general formula for a carboxylic acid

Answer 16

CnH2n+1COOH

Question 17

Why does boiling point decrease as branching occurs

Answer 17

Boiling point decreases with more branching and shorter carbon chain.
This is because more branching gives less surface contact and fewer London forces. So less energy to break London forces.

Question 18

Compounds react with chlorine in the presence of UV to form organic compounds.
Name the mechanism for this reaction

Answer 18

Free radical substitution

Question 19

What does it mean to be aliphatic

Answer 19

• carbon atoms bonded together to form straight chains
• no benzene ring
  E..g alkenes, alkanes

Question 20

What does it mean to be alicyclic

Answer 20

• Carbons bonded to form a cyclical ring
• no benzene ring
• can be saturated or unsaturated

Question 21

What does it mean to be aromatic

Answer 21

Carbons bonded to form at least one benzene ring

Question 22

What is a functional group

Answer 22

Part of the organic molecule that is largely responsible for the molecules chemical properties

Question 23

What is an electrophile

Answer 23

An electrophile is an electron pair acceptor