Intermolecular Forces Flashcards
Intramolecular bonding
“Within a molecule” refers to covalent bonding
Intermolecular bonding
“Among molecules”
Which is stronger intermolecular or intramolecular forces?
Intramolecular
Dipole-dipole forces
Forces that occur among polar molecules
Hydrogen bonding
Special case of dipole-dipole. when H is directly and covalently bonded to F, O, N. Stronger than reg dipole-dipole
London dispersion forces
Forces that occur in all substances. Weakest forces. Aka temporary dipole forces
What causes London dispersion forces?
The motion of electrons (heavier substance = stronger force)
Why are Intramolecular bonds stronger than intermolecular forces?
the attractions that hold compounds together are stronger than the attractions between molecules
Boiling Point
Temp at which the vapor pressure of the substance reaches the atmospheric pressure
How are vapor pressure and temperature related?
The are directly related (when temp goes up, so does vapor pressure)
Stronger intermolecular forces result in higher or lower boiling points?
Higher, it will take more energy to break the bonds
Characteristics of weak intermolecular forces
- particles are more likely to leave solution
- low boiling point
- more vapor
- high vapor pressure
Characteristics of strong molecular forces
- slow evaporation
- high boiling point
- less vapor
- low vapor pressure
How do we compare if intermolecular forces are the same?
We look to the molar mass. Heavier molecules have higher boiling points
