10.1 Fundamental of organic chemistry

Question 1

What is organic chemistry?

Answer 1

It is the field of chemistry that studies carbon-based compounds

Question 2

What is catenation?

Answer 2

It is the process which many identical atoms are joined together by covalent bonds, producing a straight chain, branched or cyclic structures

Question 3

Define homologous series

Answer 3

It is a series of compounds that can be grouped together based on similarities in their structure and reactions

It has the same general formula which varies from one member to another by one CH2 group

Question 4

What are hydrocarbons?

Answer 4

Compounds that contains only carbon and hydrogen

Question 5

What is the general formula for the alkane series?

Answer 5

C(n)H(2n+2)

Question 6

What’s the difference between alkanes, alkenes and alkynes?

Answer 6

Alkanes contains C-C single bonds

Alkenes contains C-C double bonds

Alkynes contains C-C triple bonds

Question 7

When does the physical properties of the members of a homologous series change?

Answer 7

It changes gradually as the length of the carbon chain increases

Question 8

What is the general formula for alcohols?

Answer 8

C(n)H(2n+1)OH

Question 9

What is the general formula for aldehydes and ketone?

Answer 9

C(n)H(2n)O
Note that both aldehydes and ketones have the same general formula but they have different structures

Question 10

WHat does the trend in boiling point result in, in terms of intermolecular forces?

Answer 10

The intermolecular forces (London Dispersion Force) increases as the carbon chain becomes longer

Question 11

What is fractional distillation?

Answer 11

It is a physical separation process that uses differences in boiling point to separate the mixtures into fractions of similar boiling point

Question 12

Describe a simple distillation apparatus?

Answer 12

A simple distillation apparatus can effectively separate volatile fractions from long-chain, non-volatile compounds

Question 13

Describe homologous series in terms of their chemical properties

Answer 13

Homologous series have similar chemical properties due to the presence of same functional group

Question 14

State and explain the trend of the boiling points of the first five members of the alkene homologous series (3)

Answer 14

Boiling points increase; Increasing size of molecule/ area of contact/ number of electrons;
Increase in strength of intermolecular/ Van der Waals’/ London dispersion forces, hence more energy required to break the intermolecular bonds

Question 15

Describe 2 features of a homologous series (2)

Answer 15

1. Same general formula
   - Successive members differ by CH2
2. Same functional group;
   - Similar or the same chemical properties
   - Gradual change in physical properties

Question 16

What is an empirical formulae?

Answer 16

It represents the simplest ratio of atoms present in a molecule

Question 17

What is a molecular formula?

Answer 17

It describes the actual number of atoms present in the molecule

Question 18

What are the 3 forms of structural formulae?

Answer 18

1. Full
2. Condensed
3. Skeletal

Question 19

Define saturated

Answer 19

Compounds that only consists of single bonds

Question 21

Define unsaturated

Answer 21

Compounds that consists of double bonds

Question 21

Compare and contrast cycloalkane and aromatic hydrocarbons structures?

Answer 21

Both are ring structures
Cycloalkanes: contains only single C-C bonds
Aromatic hydrocarbons: consists of alternating single and double C-C bonds

Question 22

What’s another name for aromatic hydrocarbons

Answer 22

Arenes

Question 23

What are synthetic compounds?

Answer 23

They are the products of reactions involving both natural and man-made compounds

Question 24

Where are natural compounds found?

Answer 24

They are found in plants and animals are synthesised by organisms

Question 25

What’s the general formula for arenes/ aromatic hydrocarbons?

Answer 25

C(n)H(2n-6)

Question 26

What’s the general formula for halogenoalkanes?

Answer 26

C(n)H(2n+1)X

Question 27

What’s the difference between aldehydes and ketones in terms of their structure

Answer 27

Aldehydes: -CHO
Ketones: -C(O)R’

Question 28

Define aliphatic

Answer 28

Relating to or denoting organic compounds in which carbon atoms form open chains (as in the alkanes), not aromatic rings

Question 29

How do you classify if a molecule is primary?

Answer 29

A primary carbon is bonded to 1 other carbon atom

Question 30

How do you classify if a molecule is secondary?

Answer 30

A secondary carbon is bonded to 2 other carbon atoms

Question 31

How do you classify if a molecule is tertiary?

Answer 31

A tertiary carbon is bonded to 3 other carbon atoms

Question 32

How are halogenoalkanes made?

Answer 32

Alkanes undergo free-radical substitution reactions with halogens and the resulting mono-substituted alkanes are known as halogenoalkanes.

Question 33

How are alcohol made?

Answer 33

Alkanes undergo free-radical substitution reactions with hydroxyl group and the resulting mono-substituted alkanes are known as alcohols.

Question 34

Define biofuels

Answer 34

They are substances whose energy is derived from carbon fixation in plants.

Question 35

What are aromatic hydrocarbons characterized by?

Answer 35

They are characterized by the presence of benzene rings

Question 36

Describe the bond length of a benzene structure

Answer 36

Benzenes bond length are intermediate in length between a single bond and a double bond. Thus having a bond order of 1.5

Benzene structures have equal bond lengths

Question 37

What is hydrogenation?

Answer 37

Hydrogenation is the addition of hydrogen to unsaturated hydrocarbons in the presence of a catalyst