Draw the skeletal structures of two different molecules that are each made of 5 carbon atoms and 12 hydrogen atoms

I got you man.

Explanation:

  h h h h h                     h h h h

h-c-c-c-c-c-h               h-c-c-c-c-h

  h h h h h                      h ↓ h h

                                       h-c-h    

                                          h

You'll just have to imagine the single line connecting the h's and c's. There are only single lines. The molecules created by the first one is a saturated hydrocarbon known as Pentane. The second is Methylbutane (isopentane).        

a physical change biology

explanation: