Bonds

The Caffeine Molecule is made up of many bonds, like any other molecule.
The elements and their electronegativity values are:
C-2.5
O-3.5
H-2.2
N-3.0
The bond between C and H has a difference of .3 which makes the bond extremely covalent.
The bond between C and O has a difference of 1so it is moderately covalent.
The bond between C and N has a  difference of .5 so the bond is extremely covalent.
The bond between N and O has a difference of  is .5 which makes the bond extremely covalent.
The bond between O and H has a difference of 1.3 which makes the bond moderately covalent.