Unit 4 - Structure of Organic Compounds

Question 1

Bonding in Carbon Compounds

Answer 1

Carbon atoms contain 6 electrons - two in first shell and four in second shell
A carbon atom can form four covalent bonds with up to four other carbon atoms

Question 2

Saturated vs Unsaturated Carbon Bonds

Answer 2

A molecule that contants only one single carbon-carbon bond is described as a saturated molecule
A molecule that contains a double or triple cabron-carbon bond is described as unsaturated molecule

Question 3

Stability of Carbon Bonds

Answer 3

Bond energy is the measure of bond strength and is the amount of energy required to break the covalent bond
^Energy ^Bond Strength

Question 4

Hydrocarbons

Answer 4

Some organic molecules are made up only carbon and hydrogen are defined as hyrdrocarbons.
Most organic molecules contain elements in addition to carbon and hydrogen including oxygen, nitrogen, sulfur or chlorine

Question 5

Functional Groups

Answer 5

A functional group is defined as an atom or a group of atoms that gives a characteristic set of chemical properties to a molecule containing these atoms.

Question 6

Class of Organic Compound - Alkane

Answer 6

Alakane
Functional group: none
Example: Ethane

Question 7

Class of Organic Compound - Alkene

Answer 7

Alkene
Functional Group: Double bond carbon
Example: Ethene

Question 8

Class of Organic Compound - Alkyne

Answer 8

Alkyne
Functional Group: Triple bond carbon
Example: Ethyne

Question 9

Class of Organic Compoound - Haloalkane

Answer 9

Haloalkane
Functional Group: halogen (group 7 elements)
R-X (where R is the carbon bond and X = F, Cl, Br, I)
Example: Chloroethane

Question 10

Class of Organic Compound - Alcohol

Answer 10

Alcohol
Functional group: Hyrdoxyl, R - OH
Example: Ethanol

Question 11

Class of Organic Compound - Amine

Answer 11

Amine
Functional Group: Amino, R - NH2
Example: Ethanomine

Question 12

Class of Organic Coumpound - Aldehyde

Answer 12

Aldehyde
Functional group: Carbonyl (attached to the a hydrogen atom)
O
II
R - C - H
Example: Ethanal

Question 13

Class of Organic Compound - Ketone

Answer 13

Ketone
Functional Group: Carbonyl (attatched to a carbon atoms on either side)
O
II
R - C - R
Example: Propanone

Question 14

Class of Organic Compound - Carboxylic Acid

Answer 14

Carboxylic Acid
Functional Group: Carboxyl
O
II
R - C - OH
Example: Ethanoic acid

Question 15

Class of Organic Compound - Ester

Answer 15

Ester
Functional Group: Carboxylate
O
II
R - C - O - R
Example: Methyl ethanoate

Question 16

Class of Organic Compound - Amide

Answer 16

Amide
Functional group: Carboxamide
O
II
R - C - NH2
Example: Ethanamide

Question 17

Class of Organic Compound - Nitrile

Answer 17

Nitrile
Functional Group: Nitrile
R - C - (triple bond) - N
Example: Ethanentrile

Question 18

General Groupings

Answer 18

Alkane + Alkene + Alkyne
Haloalkane + Alcohol + Amine
Aldehyde + Ketone + Carboxylic Acid + Ester + Amide

Question 19

Naming with number placement

Answer 19

1 - Meth 6 - He
2 - Eth 7 - Hep
3 - Prop 8 - Oct
4 - But 9 - Nona
5 - Pent 10 - Dec

Question 20

Homologous Series

Answer 20

A homologous series is a class of molecules in which each member differs by - CH2- from the previous member.
Alkanes, Alkenes, Alkynes all have homologous series
Compounds from the same homologous series contains:
- a similar structure
- a pattern to the physical properties
- similar chemical properties
- the same general formula

Question 21

Chain Isomers

Answer 21

Chain isomers are a consequence of the branching that is possible in carbon chains. The more atoms in the molecule, the more structural isomers are possible
(E.g CH6. C2H6, C3H8, all have 0 chain isomers
C4H10 has 2 chain isomers)

Question 22

Positional Isomers

Answer 22

Positional isomers only exist for molecules that contain a functional group and have a long enough carbon chain so that the different positions for the functional group are possible.

For these isomers, the molecular formula (C6H12) stay the same, however the naming increases or decreases (i.e hexane, hex-2-ane, hex-3-ane)

Question 23

Stereoisomers

Answer 23

Two types: optical and geomertic isomers

Question 24

Geometric Isomers

Answer 24

Called cis-trans isomers and can occur when there is restricted rotation somwhere in a molecule. Restricted rotation can occur about a carbon-carbon double bond or a ring

Question 25

Cis - Trans Isomers

Answer 25

Because the way electrons are arranged in a double bond, groups attached to either side of the double bond are unable to rotate freely

these isomers can only occur when each carbon atom in the double bond is attached to two different groups

Question 26

Cis - Trans Isomer Structure

Answer 26

A C
/ /
C= C
/ /
B D

Cis - Trans Isomers cannot occur if A and B are the same
Cis Isomers occur when A and C are the same
Trans Isomers occur when A and D are the same

Question 27

Alkyl Groups

Answer 27

H
I
H - C
I
H

Question 28

Determing primary, secondary and tertiary structures

Answer 28

Primary - The carbon bonded to the halogen is only bonded to one alkyl group
Secondary - The carbon bonded to the halogen is also bonded to two alkyl groups
Tertiary - The carbon bonded to the halogen is also bonded to three alkyl groups
(Same as alcohol)

Question 29

Naming Structures (Points)

Answer 29

Naming aldehydes - add ‘al’ at the end
Naming ketones - add ‘one’ at the end
Naming carboxylic acid - add ‘oic acid’ at the end
Naming amides - add ‘amide’ at the end

Question 30

IUPAC Naming Rank

Answer 30

**Highest **
Carboxyl - ‘oic acid’
Ester - ‘oate’
Amide - ‘amide’
Carbonyl (aldheyde) - ‘al’
Carboyl (Ketone) - ‘one’
Hydroxyl - ‘ol’
Amino - ‘amine’
Alkene - ‘ene’
Alkyne - ‘yne’
Halo -
**Lowest **