What is the strongest type of intermolecular force? Why?
Hydrogen bonds are the strongest intermolecular force because the dipole-dipole interaction between Hydrogen and Nitrogen, Fluorine, or Oxygen creates the strongest partial positive and partial negative charges. Hydrogen receives the partial positive while the atom receives the partial positive charge.
Explain why a lake or any given body of water does not freeze solid when the temperature is below the freezing point of water.
The answer lies within the physical properties of the water molecule. Water is most dense at 4C. The as the temperature outside drops, the water at the surface becomes colder. It's temperature drops and approaches 4C. The 4C water sinks to the bottom of the lake and is replaced by water that has not been cooled. This process continues until the entire lake has a water temperature of 4C. The water at the top of the lake then freezes. The frozen water has a lower density so it floats on top of the surface. The ice insulates the liquid water below it, so it does not freeze.
You separate the components with multiplication signs. Like terms are divided by like terms. The solution is 4a