3 B) alkanes

Question 1

3.2 recall that alkanes have the general formula CnH2n+2

Answer 1

Alkanes have the general formula CnH2n+2 . n is the number of carbons.
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Question 2

3.3 draw displayed formulae for alkanes with up to five carbon atoms in a molecule, and name the straight-chain isomers

Answer 2

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Question 3

3.4 recall the products of the complete and incomplete combustion of alkanes

Answer 3

Complete combustion gives carbon dioxide and water. eg: CH4 + O2 ==> CO2 + H2O

Incomplete combustion gives carbon monoxide and water. eg: CH4 + O2 ==> CO + H2O

Question 4

3.5 describe the substitution reaction of methane with bromine to form bromomethane in the presence of UV light.

Answer 4

In UV light bromine and methane will form bromomethane:

CH4 + Br2 ==> CH3Br + HBr

What has happened in this reaction is bromine has taken the place of hydrogen (substitution)