IMFs + solubility & phase changes

forces/interactions between molecules

stronger the IMF, the harder it is to…

change phases

types of IMF in increasing strength

1) london dispersion forces (LDF)

2) dipole-dipole forces (d-d)

3) hydrogen bonding

4) ion-dipole force ← strongest!!

dipole-dipole force =

ex: H - Cl

2 polar molecules (polar-polar) interacting

Hydrogen bonding

• a special variation of dipole-dipole that is …

• a molecule can H-bond to another molecule if ti has a hydrogen bond to…___,___, or ___

STRONGER

N, O, or F ← the most electronegative elements on the P.T.

Ion - Dipole force

• force between a ____ molecule and an ____ (___ charge)

• force between a polar molecule and an ion (full charge)

london dispersion forces

• present in ___ molecules, but when first learning about it, it can be easier to think of non-polar molecules since it is the only IMF present.

• this comes from electrons ______ around, creating an _________________ dipole

  • this effect is also present in _____ molecules, adding to the ______ of their ________ dipole

ALL;

moving; instantaneous

polar; strength; permanent

the ability for electrons to move around is proportional to the molecule’s ___________

• Generally speaking, polarizability increases as the number of ________ increases

  • can consider this 2 ways:

    • use _____ atom

    • include ____ atoms

polarizability

electrons

bigger

more

low freezing point =

low/weak IMF

high boiling point =

high/strong IMF

quick note on solubility

• “____ dissolves ______”

• ____ dissolves ____

• ________ dissolves ________

• they don’t ______ each other

• like dissolves like

• polar; polar

• nonpolar nonpolar

• dissolve

phase changes

1. s → l :

2. l → s :

3. l → g :

4. g → l :

5. s → g :

6. g → s :

1. melting/fusion

2. freezing

3. evaporation/vaporization

4. condensation

5. Sublimation

6. deposition

phase diagram

• pressure vs. temp (in celsius)

*know phase diagram of H2O