UNIT 4

Question 1

different intermolecular forces

Answer 1

london dispersion forces, dipole-dipole forces, hydrogen bonding, charge dipole forces, charge - charge forces

Question 2

London Dispersion Forces

Answer 2

Also known as Van der Waals instantaneous dipole-induced dipole forces

• exists between all atoms and molecules and are always attractive
• as boiling points increase, LDF also increase
• strength increases as the number of electrons in the molecule increases
• in general weak in comparison to other forces

Question 3

dipole - dipole interactions

Answer 3

-arise from favorable alignment in molecules

• does not have this interaction if the electronegativity is the same (O2, N2, etc) or if the polarity is weak (they are not that far apart, CH4)
• strong

Question 4

charge-dipole interactions

Answer 4

• charged particle (i.e an ion) interact with a polar molecule with a permanent dipole - theres a postive end and negative end

Question 4

charge-charge or ion ion interactions

Answer 4

very strong and involves ionic solids or ionic liquids

Question 5

hydrogen bonding

Answer 5

a strong dipole dipole force in molecules with a hydrogen atom bonded to an electronegative atom (N,O, F)

strong force

Question 6

sublimation

Answer 6

solid to gas

Question 7

deposition

Answer 7

gas to solid

Question 8

vaporization

Answer 8

liquid to gas

Question 9

condensation

Answer 9

gas to liquid

Question 10

freezing

Answer 10

liquid to solid

Question 11

melting

Answer 11

solid to liquid

Question 12

triple point

Answer 12

where gas liquid and solid all exists

Question 13

in a P-T phase diagram

Answer 13

gas is on the bottom portion, liquid is to the top right ish and solid is to the far left

Question 14

critical point

Answer 14

end of gas- liquid boundary

Question 15

what happens to density if the pressure increases or the temp decreases for a stable phases?

Answer 15

it gets more dense

Question 16

whats a supercritical fluid?

Answer 16

this is what happens beyond the critical point so this fluid exhibits both properties of liquid and gas

Question 17

which phase is favored at low temp and at high pressure?

Answer 17

solid

Question 18

which phases is favored at high temp and low pressure?

Answer 18

gas

Question 19

what happens to the critical temp for substances with weak intermolecular interactions?

Answer 19

is relatively low

Question 20

substances with strong intermolecular interactions tend to form a liquid at very____ temps

Answer 20

large

Question 21

volatile liquids

Answer 21

have high vapor pressures which tend to evaporate readily from an open container

when the vapor pressure equals the external pressure, bubble of vapor form within the liquid and it boils

Question 22

Go study the chart in ur one note notebook