Nomenclature (introduction to organic chemistry)

Question 1

Name the roots of the first 6 carbons

Answer 1

1 = meth
2 = eth
3 = prop
4 = but
5 = pent
6 = hex

Question 2

What are functional groups?

Answer 2

A reactive group - react in same way whatever length of hydrocarbon chain

Question 3

Outline the general formula and suffix (if any) of alkanes

Answer 3

CnH2n+2, -ane

Question 4

Outline the general formula and suffix (if any) of alkenes

Answer 4

R—CH=CH—R, -ene

Question 5

Outline the general formula and prefix (if any) of halogenoalkanes

Answer 5

R—X (X=halogen), fluoro- or chloro- or bromo- or iodo-

Question 6

What is a homologous series?

Answer 6

A family of organic compounds with the same functional group, but different carbon chain lengths

Question 7

(Homologous series)

Why does chain branching generally reduce melting points?

Answer 7

Because the molecules pack together less well

Question 8

(Homologous series)

What does the length of carbon chain have an effect on? What does it not have an effect on?

Answer 8

• Little effect on the chemical reactivity of the functional group
• Affects physical properties (melting point, boiling point, and solubility) — melting points and boiling points increase as no. of carbon atoms in the chain increases. This is because the intermolecular forces increase.

Question 9

What are isomers? Name two types of isomerism in organic chemistry

Answer 9

Isomers are molecules that have the same molecular formula but whose atoms are arranged differently.
Structural isomerism and stereoisomerism

Question 10

Define structural isomerism

Answer 10

Molecules that have the same molecular formula but different structural formulae

Question 11

Describe the 3 types of structural isomerism

Answer 11

• Positional isomerism — functional group is attached to main chain at different points
• Functional group isomerism — there are different functional groups
• Chain isomerism — the hydrocarbon chain is arranged differently

Question 12

Define stereoisomerism

Answer 12

Compounds have the same structural formula but differ in arrangement of bonds in space

Question 13

Name the 2 types of stereoisomerism

Answer 13

E-Z isomerism, optical isomerism

Question 14

Why can’t Z- and E-isomers be easily converted from one another?

Answer 14

Because there is no rotation of substituted groups around a double bond so Z- and E-isomers are separate compounds and are not easily converted from one to the other.

Question 15

What does E-Z isomerism tell us about?

Answer 15

The positions of substituents at either side of a C=C double bond. Two substituents may either be on the same side of the bond (Z) or on opposite sides (E)