Geoffrey places a 9-gram piece of an unknown substance into a graduated cylinder that is filled with 12 mL of water, and the water rises from the 12 mL line to the 15 mL line. What is the density of the unknown substance? A) 108 g/mL
B) 3 g/mL
C) 0.8 g/mL
D) 0.6 mL

As cooking food that has to go in the oven

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.