2. Hydrocarbons

Question 1

What is a fuel?

Answer 1

A substance which burns to release energy

Question 2

What is a hydrocarbon?

Answer 2

A compound which contains hydrogen and carbon only

Question 3

What is a homologous series?

Answer 3

A family of compounds which contain the following:

• The same general formula
• Similar chemical properties
• Gradually changing physical properties

Question 4

What is the order of prefixes for the amount of carbon atoms in a molecule?

Answer 4

• meth
• eth
• prop
• but
• pent
• hex
• hept
• oct

Question 5

What are isomers?

Answer 5

Compounds which have the same molecular formula but different structural formula

Question 6

How can we determine if a compound is saturated or unsaturated?

Answer 6

The bromine test:

• Alkane, saturated, no change in colour
• Alkene, unsaturated, rapidly decolourises as C=C breaks and bromine “adds in”

Question 7

What are addition reactions?

Answer 7

When a substance is added to an unsaturated (C=C) molecule. The double bond breaks and a saturated (C-C) is formed. The substance added joins to the two carbon atoms from the C=C