Exam 2 - Intermolecular forces

Question 1

Define Intermolecular forces

Answer 1

Force of attraction that occurs between atoms, molecules, and ions due to proximity in space

Question 2

Are intermolecular forces stronger or weaker than intramolecular forces (covalent, ionic, metallic bonds)

Answer 2

Weaker

Question 3

Why do intermolecular forces APPEAR stronger

Answer 3

Due to large number of interactions

Question 4

What affects the strenght of attraction?

Answer 4

Magnitude of charge (Real of partial) and distance between species

Question 5

Polarity and what is referred as?

Answer 5

Separation of electric charge along a bond due to differences in the electronegativity of the bonded atoms

Electric dipole or dipole moment

Question 6

The stronger the intermolecular forces, the more energy required to _______ the surface area.

Answer 6

Increase

e.g. water drops on a penny, water builds up

Question 7

Capillary action

Answer 7

Spontaneous rising of a liquid in a narrow tube or movement of liquid up a paper towel against the pull of gravity, results from cohesive and adhesive forces.

think cap gas at childrens

Question 8

Cohesive

Answer 8

Hold the liquid molecules together

Question 9

Adhesive

Answer 9

Attraction of outer molecules to the containers surface

Question 10

Viscosity

Answer 10

liquids resistance to flow.
- the amount of energy needed to move an object through fluid

e.g. Oil has a higher viscosity than water

Question 11

Receptor-drug binding

Answer 11

Vast majority of drug compounds bind to receptors through intermolecular forces than chemical bonds.

Question 12

What does receptor-drug binding determine?

Answer 12

Determines properties such as efficacy, potency and toxicity.

Question 13

Phase changes

Answer 13

Substance changing phases with respect to temperature and pressure.

Ice to solid, liquid to gas, etc.

Question 14

Liquid freezes at higher temperatures at higher or lower pressures?

Answer 14

Lower

Question 15

Higher the pressure, the ______ temperature needed to freeze.

Answer 15

Lower

Question 16

Solubility

Answer 16

Depends on attractive forces of solute and solvent, substances with similar polarity will be soluble (solid in liquid) or miscible (liquid in liquid aka like dissolves like)

Question 17

Van der waals (london dispersion) forces

Answer 17

interaction arising from formation of induced dipoles between two non-polar molecules

weakest of intermolecular forces

Question 18

Dipole-dipole interactions

Answer 18

occurs in all polar molecules, relatively strong interaction depending on nature of dipoles involved.

Question 19

Hydrogen bonding

Answer 19

Very strong, specialized dipole-dipole interaction.

H-bond donors -> molecule providing hydrogen
H-bond acceptor -> molecule that attracts hydrogen

Question 20

Hydrogen bonding [X–H - - - :Y] is strongest when

Answer 20

X and Y are N, O, and F.

Question 21

Electrostatic interactions

Answer 21

Ionic interactions between a cationic portion and anionic portion.

Effective at distances further than other types of interactions.

Persist longer than other interactions

Question 22

Covalent bonds

Answer 22

Strongest interaction, limited reversibility, seldomly formed.

Question 23

Drug binding picture with different interactions

Answer 23

Question 24

Another Drug binding picture with different interactions

Answer 24

Question 25

Determine the various intermolecular forces for Dibucaine