Alkanes - properties

Question 1

What are the trends of alkanes?

Answer 1

• The shorter the chain, the lower the boiling point (first 4 are gases at room temperature) - because there are fewer intermolecular forces to break
• The shorter the chain, the more volatile the alkane is (evaporates more easily - better fuel due to lower boiling points)
• The longer the chain, the more viscous the alkane is (thicker and less runny)
• The shorter the chian, the more flammable the alkane is (better fuel)

Question 2

What is produced in the complete combustion of an alkane?

Answer 2

• Alkane + oxygen = carbon dioxide + water (+ energy)

Question 3

What is interesting of the properties of alkanes?

Answer 3

• Homologous series molecules: have similair properties

Question 4

What is the main use of a hydrocarbon?

Answer 4

• As a fuel
• Releases lots of energy when burnt with oxygen

Question 5

What type of reaction is combustion?

Answer 5

• Exothermic