25.15 Intermolecular Forces

Question 1

intermolecular forces

Answer 1

weak interactions between NEUTRAL molecules (not actual bonds)

Question 2

ion-dipole force

Answer 2

polar molecules attracted to ions

Question 3

dipole-dipole force

Answer 3

attractions between + end of one polar molecule with the - end of another

Question 4

dipole-induced dipole force

Answer 4

permanent dipole in a polar molecule may induce a dipole momentarily in a NP molecule

Question 5

London-dispersion force

Answer 5

induced dipole in a NP molecule may induce a dipole momentarily in another NP molecule

Question 6

what does an atom need to have London dispersion forces?

Answer 6

just needs electrons

Question 7

what increases dispersion forces?

Answer 7

increased size of molecule

Question 8

what decreases dispersion forces?

Answer 8

amount of branching (decrease SA for dispersion forces)

Question 9

what does stronger intermolecular forces lead to?

Answer 9

↑ MP/BP = ↑ viscosity = ↓ vapor pressure

Question 10

what is required for a hydrogen bond?

Answer 10

1) covalent bond between H and N/O/F

2) lone pair on N/O/F atom

Question 11

how does intermolecular hydrogen bond affect MP/BP?

Answer 11

↑ MP/BP

Question 12

how does intramolecular hydrogen bond affect MP/BP?

Answer 12

↓ MP/BP

Question 13

vapor pressure

Answer 13

how easy it is to evaporate a substance, the pressure exerted by the gaseous phase during evaporation

Question 14

volatile

Answer 14

compounds with high vapor pressures, easy to evaporate and have weak intermolecular forces

Question 15

what increases vapor pressure?

Answer 15

↑ VP = ↑ intermolecular forces = ↑ Temp

Question 16

how does H-bonding affect MP/BP?

Answer 16

depends on if its intermolecular or intramolecular H-bonding