Unit 2, Topic 6 - Homologous Series

Question 1

Which elements are present in alkanes?

Answer 1

Carbon and hydrogen

Question 2

Name the first 8 alkanes and write the formula for them.

Answer 2

Methane, CH4
Ethane, C2H6
Propane C3H8
Butane C4H10
Pentane C5H12
Hexane C6H14
Heptane C7H16
Octane C8H18

Question 3

What is the general formula for alkanes?

Answer 3

Cn H 2n +2

Question 4

What type of bonding do alkanes have?

Answer 4

Covalent

Question 5

Be able to give the name of the alkane, write the molecular formula, structural formula, and shortened structural formula.

Answer 5

Practice

Question 6

As the length of the carbon chain increases what happens to the melting and boiling points of the alkanes?

Answer 6

As the C chain length increases the boiling point increases. As the size of the molecule increases, the intermolecular forces increase.

Question 7

What does a substance react with during combustion?

Answer 7

Oxygen

Question 8

When an alkane is fully burnt in oxygen what are the 2 products formed?

Answer 8

Carbon dioxide and water

Question 9

Be able to write a balanced equation to show the reaction for the complete combustion of any alkane.

Answer 9

Practice

Question 10

Name the substances that would form if there is incomplete combustion of any alkane.

Answer 10

Carbon monoxide/ or even carbon and water

Question 11

Be able to draw a full structural formula for any branched chain alkane from the name.

Answer 11

Practice

Question 12

What is meant by the term isomer?

Answer 12

Same molecular formula but a different structural formula.

Question 13

Name three things that are different for isomers.

Answer 13

Structure, name, properties

Question 14

Name the elements present in cycloalkanes.

Answer 14

Carbon, hydrogen

Question 15

Name and give the formula for the first 8 members of the cycloalkanes.

Answer 15

Cyclopropane, C3H6
Cyclobutane C4H8
Cyclopentane C5H10
Cyclohexane C6H12
Cycloheptane C7H14
Cycloctane C8H16
Cyclononane C9H18
Cyclodecane C10H20

Question 16

What is the general formula for cycloalkanes?

Answer 16

Cn H 2n

Question 17

Be able to write the molecular formula and full structural formula for any named cycloalkane.

Answer 17

Practice

Question 18

What are the products of the combustion of cycloalkanes?

Answer 18

Carbon dioxide and water

Question 19

WHat type of carbon-to-carbon bond do alkenes have in their structure?

Answer 19

Carbon/carbon double bond

Question 20

Be able to draw and identify isomers of alkenes and cycloalkanes.

Answer 20

Practice

Question 21

Compounds with at least one carbon-to-carbon double bond are called…

Answer 21

unsaturated

Question 22

What would you use to test a compound to see if it contained a carbon-to-carbon double bond?

Answer 22

Bromine water

Question 23

What would you expect to observe if the compound did have a carbon-to-carbon double bond?

Answer 23

Goes from orange to colourless.

Question 24

Write an equation to show the reaction between prop-1-ene and bromine

Answer 24

Practice

Question 25

Write an equation to show how ethene will react with hydrogen to make ethane.

Answer 25

C2H4 + H2 —> C2H6

Question 26

What is the name given to this type of reaction ? (ethene reacting with hydrogen to make ethane)

Answer 26

Hydrogenation