1 methane   CH4   All single bonds
2 ethane C2H6 All single bonds
3 acetylene C2H2 Triple bond between the carbon atoms
4 propane C3H8 All single bonds
5 butane C4H10 All single bonds
6 pentane C5H12 All single bonds
7 hexane C6H14 All single bonds
8 heptane C7H16 All single bonds
9 octane C8H18 All single bonds
10 butadiene C4H6 Has two double bonds between two carbons.  There's also a single bond between two carbons.
11 benzene C6H6 A ring of 6 carbon atoms with three double bonds and  three single bonds between the carbons.
12 cyclohexane C6H12 A "rectangle" of six carbon atoms.  Each carbon has two Hydrogens with  it
13 ethylene C2H4 No hint

How can we change hydrocarbons into things we want?

14 In ethane, replace one hydrogen with an oxygen that has a hydrogen bonded to it and you have ethyl alcohol
15 Replace a hydrogen on any hydrocarbon with an amino group.  An amino group is a nitrogen atom with two hydrogens on it.
16 Ether.  To make an ether, all you do is hook two hydrocarbons together with an oxygen atom.  Each oxygen atom has two bonds.  Draw dimethyl ether.
17 Alkenes.  To make an alkene, just stick an extra carbon atom onto a hydrocarbon.  This carbon atom is double bonded to the hydrocarbon and it has two hydrogens on it.  Draw ethyl ketone.