Introduction to organic chemistry

Question 1

What is organic chemistry?

Answer 1

Organic chemistry is the study of covalent compounds primarily made of carbon, often including hydrogen, oxygen, nitrogen, and halogens.

Question 2

What is a functional group in organic chemistry?

Answer 2

A functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule.

Question 3

What is a homologous series?

Answer 3

A homologous series is a family of compounds with the same functional group, similar chemical properties, and each member differing by a CH₂ unit.

Question 4

What is the general formula of alkanes?

Answer 4

CₙH₂ₙ₊₂

Question 5

Define isomerism.

Answer 5

Isomerism occurs when compounds have the same molecular formula but different structural or spatial arrangements of atoms

Question 6

What is the difference between structural isomers and stereoisomers?

Answer 6

Structural isomers differ in the arrangement of atoms in their structure, while stereoisomers have the same structural formula but a different arrangement of atoms in space.

Question 7

What is the empirical formula?

Answer 7

The empirical formula shows the simplest whole number ratio of atoms of each element in a compound.

Question 8

What is the molecular formula?

Answer 8

The molecular formula shows the actual number of atoms of each element in a molecule.

Question 9

What is free radical substitution?

Answer 9

Free radical substitution is a reaction mechanism where a hydrogen atom in an alkane is replaced by a halogen atom, initiated by UV light.

Question 10

What is the difference between saturated and unsaturated organic compounds?

Answer 10

Saturated compounds have only single bonds between carbon atoms (e.g., alkanes),

Unsaturated compounds contain double or triple bonds (e.g., alkenes, alkynes).

Question 11

What is an electrophile?

Answer 11

a molecule / substance that acts as an electron pair acceptor

Question 12

What is a nucleophile?

Answer 12

a molecule / substance that donates electrons

Question 13

Free Radical

Answer 13

an uncharged molecule with an unpaired electron

Question 14

Homolytic fission

Answer 14

splitting of a covalent bond, each atom retains 1 electron from the bonding pair

Question 15

Heterolytic Fission

Answer 15

splitting of a covalent bond, one atom retains both electrons from the bonding pair

Question 16

Initiation

Answer 16

an initial chemical reaction which triggers further reactions

Question 17

Propagation

Answer 17

a secondary reaction where there is no net gain/loss of free radicals

Question 18

Termination

Answer 18

• final step in chain reaction
• reactive intermediate becomes inactive

Question 19

Addition

Answer 19

a reaction where two or more molecules reach to form a larger molecules

Question 20

Substitution

Answer 20

a reaction where an atom or group is replaced by another atom or group

Question 21

Elimination

Answer 21

a reaction where two substituents are removed from a molecule by a mechanism in 1-2 steps

Question 22

Cis isomer

Answer 22

both of the highest priority groups are on the same side, above or below C=C bond

Question 23

Trans isomer

Answer 23

highest priority groups positioned diagonally from each other on opposite sides of the C=C

Question 24

Chiral centre

Answer 24

a carbon atom with four different groups bonded to it
- a compound can have more than one chiral centre
- displays optical isomerism

Question 25

Molecular formula

Answer 25

actual number of atoms of each element in a molecule

Question 26

Structural formula

Answer 26

shows the structure carbon by carbon with hydrogens and functional groups attached

Question 27

Displayed formula

Answer 27

shows how all the atoms are arranged and every bond between them

Question 28

Skeletal formula

Answer 28

• only shows the bonds on carbon skeleton
• C, H atoms not shown
• functional groups shown