How do I know what intermolecular forces are acting in substances?
I'm trying to figure out what forces are acting in H20.
I know that it has hydrogen bonding. I'm thinking it's not dipole-dipole. My only other choices are LDF (nonpolar atoms) and LDF (nonpolar molecules).

Would the forces acting on H2O be H-bonding and LDF (nonpolar atoms)? The molecule is polar (right?) so I'm hesitant to say LDR (nonpolar molecule).

I've already worked out the shape and lewis and all that, I'm just having a really tough time understanding how you determine intermolecular forces. :(

Question

How do I know what intermolecular forces are acting in substances? 
I'm trying to figure out what forces are acting in H20.
I know that it has hydrogen bonding. I'm thinking it's not dipole-dipole. My only other choices are LDF (nonpolar atoms) and LDF (nonpolar molecules).

Would the forces acting on H2O be H-bonding and LDF (nonpolar atoms)? The molecule is polar (right?) so I'm hesitant to say LDR (nonpolar molecule).

I've already worked out the shape and lewis and all that, I'm just having a really tough time understanding how you determine intermolecular forces. :(

ipwnbunnies · Answer

All molecules experience London Dispersion forces.
HOWEVER, hydrogen bonding between water molecules is more prominent. Hydrogen bonding occurs between molecules where there are hydrogen atoms connected to oxygen, nitrogen, or fluorine atoms. I hope that makes sense. .-.

So, like in water, we know it's a simple model of 2 H's connected to 1 O  for a molecule. Well, the H of one molecule is strongly attracted to the oxygen atom of another molecule.