How many types of hydrocarbons are there?

According to the IUPAC system which type of compound is shown by the given structure:

Petroleum is a mixture of different hydrocarbons.

Which method is used for separating the components of petroleum?

Write the molecular formula of propane.

Which of the following compounds are alkanes?

${\mathrm{C}}_2{\mathrm{H}}_4, {\mathrm{C}}_3{\mathrm{H}}_4, {\mathrm{C}}_4{\mathrm{H}}_8, {\mathrm{C}}_5{\mathrm{H}}_{12}, {\mathrm{C}}_5{\mathrm{H}}_8, {\mathrm{C}}_3{\mathrm{H}}_8, {\mathrm{C}}_6{\mathrm{H}}_6$.