Intermolecular Forces Flashcards
1
Q
What are Intermolecular Forces? How many are there?
A
Intermolecular Forces (IMFs) are forces that hold atoms together within a molecule
There are 4 types of IMFs, they are:
- London Dispersion Forces (weakest)
- Dipole-Dipole Forces
- Hydrogen-Bonding Forces
- Ion-Dipole Forces (strongest)
(Disperson and Dipole-Dipole forces are Van der Waals forces)
2
Q
What are London Dispersion Forces?
A
- Weakest IMF
- Van Der Waals force
- Exists in all compounds
- Only IMF present for Nonpolar Covalent molecules
3
Q
What are Dipole-Dipole forces?
A
- Second-weakest IMF
- Van der Waals force
- Exists in Polar Covalent molecules
4
Q
What are Hydrogen-Bonding forces?
A
- Second-strongest IMF
- Exists when Hydrogen is bonded to Nitrogen, Oxygen, or Flourine (H + N, O, F)
5
Q
What are Ion-Dipole forces?
A
- Strongest IMF
- Exists in mixtures of Ionic & Polar Compounds
6
Q
What are trends of IMFs related to strength?
A
As IMF strength increases:
- Melting/Boiling Point increases
- Surface Tension increases
- Viscocity increases
- Capillary Action increases
7
Q
What is Surface Tension?
A
“Skin” on surface of a liquid that allows it to resist external force
8
Q
What is Viscocity?
A
Resistance of a liquid to flow
(peanut butter has a greater viscocity than water)
9
Q
What is Capillary Action?
What is Cohesion? What is Adhesion?
A
Liquid’s ability to flow against gravity up a narrow tube
- Can only occur when a liquid’s adhesion is greater than its cohesion
- Cohesion: Attraction between molecules within a liquid
- Adhesion: Attraction between liquid and external molecules
