A mixture of He, N, and Ar has a pressure of 23.5 atm at 28.0 °C. If the partial pressure of He is 2247 torr and that of Ar is 1329 mm Hg, what is the partial pressure of N,?
PN =
atm

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.

Its not chemical its not radiation and its not convection because there is not movement of fluids so it is thermal conduction