ALKANES

Question 1

Definition: Aliphatic

Answer 1

Containing Carbon atoms joined together in straight or branched chains

Question 2

Definition: Alicyclic

Answer 2

Containing Carbon atoms joined together in a ring that is not aromatic

Question 3

Definition: Aromatic

Answer 3

Containing one or more benzene rings

Question 4

Definition: Saturated

Answer 4

Containing only single bonds

Question 5

Definition: Unsaturated

Answer 5

Containing a multiple carbon-carbon bond

Question 6

Definition: Homologous group

Answer 6

A series of organic compounds having the same functional group but with each successive member differing by CH2

Question 7

Definition: A functional group

Answer 7

A group of atoms responsible for the characteristic reactions of a compound

Question 8

General formula for alkanes

Answer 8

Cn H2n+2

Question 9

General formula for cycloalkanes

Answer 9

Cn H2n

Question 10

General formula for alkynes

Answer 10

Cn H2n-2

Question 11

Definition: Empirical formula

Answer 11

The simplest whole number ratio of atoms of each element present in a compound

Question 12

Definition: Skeletal formula

Answer 12

A simplified organic formula, with the hydrogen atoms removed from alkyl chains, leaving just a carbon skeleton and associated functional groups

Question 13

Definition: General formula

Answer 13

The simplest algebraic formula of a member of a homologous series

Question 14

Definition: Molecular formula

Answer 14

The actual number of atoms of each element in a molecule

Question 15

Definition: Structural formula

Answer 15

The minimal detail that shows the arrangement of atoms in a molecule

Question 16

Definition: Displayed formula

Answer 16

The relative positioning of all the atoms in a molecule including the bonds between them

Question 17

Functional group of aldehyde

Answer 17

CHO

Question 18

Functional group of ketone

Answer 18

C(CO)C

Question 19

Functional group of carboxylic acid

Answer 19

COOH

Question 20

Definition: Structural isomers

Answer 20

Molecules with the same molecular formula but different structure

Question 21

List the 3 ways structural isomers can occur

Answer 21

• Chain isomers: The hydrocarbon chain may be branched or unbranched
• Position isomers: The hydrocarbon chain stays the same but the functional group is found in different positions along the chain
• Functional group isomers: The functional group is different eg. Alkenes and cycloalkanes

Question 22

What is the effect of branching on boiling point?

Answer 22

More branching means a lower boiling point because the contact area between molecules is smaller and therefore the London forces are weaker and therefore less energy is required to overcome them.

Question 23

Why are alkanes relatively unreactive?

Answer 23

Alkanes only contain C-C and C-H bonds which are very strong and therefore hard to break. The are also non-polar so they can attract other species either.

Question 24

General formula for the complete combustion of a hydrocarbon of formula CxHy

Answer 24

CxHy + (x + 1/4y)O2 -> xCO2 + 1/2yH2O

Question 25

What condition is needed for an alkane to react with a halogen and what type of reaction is this?

Answer 25

UV light + substitution reaction

Question 26

Definition: Radical

Answer 26

A radical is a species with a single unpaired electron

Question 27

Name the 3 stages of free radical substitution

Answer 27

Initiation, Propagation, Termination

Question 28

Definition: Homolytic fission

Answer 28

The breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals

Question 29

Three limitations of using radical substitution in organic synthesis

Answer 29

1. Further substitution can occur 2. Substitution at different points in the C chain can happen 3. The C chain might double in length