Functional Groups and Homologous Series

Question 1

what is a functional group

Answer 1

an atom or a group of atoms that give a compound some distinct and predictable properties

Question 2

what is the functional group of alcohols and carboxylic acids

Answer 2

• OH

- COOH

Question 3

what is a homologous series

Answer 3

• a set of compounds with the same functional group
• that therefore have similar chemical and physical properties that show a gradation
• and have the same general formula

Question 4

what is a gradation

Answer 4

a gradual change from one to the next

Question 5

what homologous series are mainly used as fuels

Answer 5

alkanes

Question 6

what is the general formula of an alkane

Answer 6

CnH2n+2

Question 7

what is the general formula of an alkene

Answer 7

CnH2n

Question 8

what is the general formula of a halogenoalkane

Answer 8

CnH2n+1X (C2H5Br or CH3CH2Br)

Question 9

what is the general formula of an alcohol

Answer 9

CnH(2n+1)OH

Question 10

what are the products of completely burning an alkane or hydrocarbon in air (oxygen)

Answer 10

hydrocarbon + oxygen = water + carbon dioxide

Question 11

what is the trend in the boiling point across the alkanes as the carbon chain length increases

Answer 11

• the boiling point increases
• longer chain length and more atoms results in stronger intermolecular forces of attraction holding the hydrocarbon together
• which requires more energy to overcome