3.1 Introduction To Organic Chemistry

Question 1

Overview of the Formulae of Organic Compounds Table:

Answer 1

Question 2

Nomenclature of Organic Compounds Table:

Answer 2

Question 3

Functional Group, Prefix / Suffix, and Example of Alkenes:

Answer 3

Question 4

Functional Group, Prefix / Suffix, and Example of Alcohols:

Answer 4

Question 5

Functional Group, Prefix / Suffix, and Example of Haloalkanes:

Answer 5

Question 6

Functional Group, Prefix / Suffix, and Example of Aldehydes:

Answer 6

Question 7

Functional Group, Prefix / Suffix, and Example of Ketones:

Answer 7

Question 8

Functional Group, Prefix / Suffix, and Example of Carboxylic Acids:

Answer 8

Question 9

Functional Group, Prefix / Suffix, and Example of Nitriles:

Answer 9

Question 10

Functional Group, Prefix / Suffix, and Example of Amines:

Answer 10

Question 11

Functional Group, Prefix / Suffix, and Example of Esters:

Answer 11

Question 12

How do we position side chains or functional groups in a structural formula?

Answer 12

If there are any side-chains or functional groups present, then the position of these groups is indicated by numbering the carbon atoms in the longest chain starting at the end that gives the lowest possible numbers in the name.
The hydrocarbon side-chain is shown in brackets in the structural formula
CH3CH(CH3)CH2CH3

Question 13

Naming Side Chains

What do we do if there are more than one of the same alkyl side-chain or functional groups?

Answer 13

• If there are more than one of the same alkyl side-chain or functional groups, di- (for two), tri- (for three) or tetra- (for four) is added in front of its name
• The adjacent numbers have a comma between them
• Numbers are separated from words by a hyphen

Question 14

Naming Multiple Side Chains

How do we name more than one alkyl side-chain?

Answer 14

If there is more than one type of alkyl side-chain, they are listed in alphabetic order

Question 15

Functional Groups & their Nomenclature Table:

Answer 15

Question 16

What is A Skeletal Formula?

Answer 16

• Shows the simplified organic formula, shown by removing hydrogen atoms from alkyl chains
• leaving just a carbon skeleton and associated functional groups.

Question 17

What is the general rule for naming carbon chains?

Answer 17

Question 18

What are Straight-Chain Organic Molecules?

Answer 18

Straight-chain organic molecules are those in which the carbon atoms are connected to each other in one continuous chain

Pentane is a straight-chain organic molecule as the carbon atoms are connected in one continuous chain

Question 19

What are Branched Organic Molecules?

Answer 19

Branched organic molecules have side groups attached to the main chain of carbon atoms

2-methylbutane is a branched organic molecule as the main chain (consisting of 4 carbon atoms) has a methyl branch

Question 20

What are Cyclic Organic Molecules?

Answer 20

Cyclic organic molecules are those in which the carbon atoms are connected to each other in a ring shape

Cyclopentane is a cyclic organic molecule as the carbons are attached to each other in a ring structure

Question 21

What are Structural Isomers?

Answer 21

Structural isomers are compounds that have the same molecular formula but different structural formulae

E.g. propene and cyclopropane

Question 22

What are the the three different types of Structural Isomers

Answer 22

• Chain isomerism
• Positional isomerism
• Functional group isomerism

Question 23

What is Chain Isomerism?

Answer 23

• Chain isomerism is when compounds have the same molecular formula, but their longest hydrocarbon chain is not the same
• This is caused by branching

E.g. pentane and 2,2-dimethylpropane

Both compounds are made up of the same atoms, however the longest carbon chain in pentane is 5 and in 2,2-dimethylpropane it is 3 (with two methyl branches)

Question 24

What is Positional Isomerism?

Answer 24

• Positional isomers arise from differences in the position of a functional group in each isomer
• The functional group can be located on different carbons
• For example, butan-1-ol and butan-2-ol

Both compounds have an alcohol group and are made up of 4 carbons, 10 hydrogens and one oxygen, however in butanol the functional group is located on the first carbon and in 2-butanol on the second carbon

Question 25

What is Functional Group Isomerism?

Answer 25

• When different functional groups result in the same molecular formula, functional group isomers arise
• The isomers have very different chemical properties as they have different functional groups
• For example, butanol and ethoxyethane

Both compounds have the same molecular formula however butanol contains an alcohol functional group and ethoxyethane an ether functional group

Question 26

How can we deduce all possible isomers for organic compounds knowing their molecular formula?

Answer 26

• Step 1: Draw the structural formula of the compound
• Step 2: Determine whether it is a stereo or structural isomer
• Step 3: Determine whether it is a functional group, chain or positional isomerism

Question 27

What are Sterioisomers?

Answer 27

Stereoisomers are compounds that have the same atoms connected to each other, however the atoms are differently arranged in space

• Molecules with the same structural formula
• But the atoms are arranged differently in space

Question 28

What is E/Z Isomerism?

Answer 28

• E/Z nomenclature is used to distinguish between the isomers
• Z isomers have functional groups on the same side of the double bond/carbon ring
• E isomers have functional groups on opposite sides of the double bond/carbon ring
• To discuss E / Z isomers, we will use an alkene of the general formula C2R4:

• You may see this type of isomerism referred to in other sources as cis/trans isomerism
• This is a special case of E/Z isomerism
• A “cis” isomer would essentially be the same as a “Z” isomer and a “trans” isomer would also essentially be the same as an “E” isomer