Alkanes and Alkenes

What is a homologous series?

A homologous series is a group of molecules which have the same general formula, the same chemical properties and show trends in their physical properties. Examples of homologous series include alkanes and alkenes.

What is the difference between an alkane and an alkene?

An alkane is a hydrocarbon with only single carbon bonds. An alkene is a hydrocarbon which has at least one double carbon bond.

Give the general formula for the alkane homologous series.

What is formed when butane is burnt in an environment with a lack of oxygen?

When butane is burnt in insufficient oxygen, incomplete combustion takes place. Incomplete combustion results in the formation of carbon monoxide (CO) and water. If there is even less oxygen present, carbon can also be formed as a product.

Describe the reaction that takes place when bromine is added to propene. What observations would be made?

Bromine reacts with alkenes in an addition reaction. This results in the formation of dibromopropane. A colour change of orange to colourless would be seen.

Describe the reaction that takes place when bromine is added to propane. What conditions are needed for this reaction?

Bromine reacts with alkanes in substitution reactions. Bromopropane and hydrogen bromide are formed. UV light is needed for this reaction to happen.