Intermolecular Forces Flashcards
Intramolecular Force
Strong attractions between atoms in a single molecule
Intermolecular Force
Attraction between different molecules that causes them to be held together
Individual intermolecular forces are always ___ than intramolecular forces.
Weaker
IMFs and bonds depend on ___ and ___.
Charge/polarity: larger charge=stronger attraction
Distance: shorter distance=stronger attraction
Rank IMF energy from strongest to weakest
Ion-dipole
H-bond
Dipole-dipole
Dipole-induced dipole
Dispersion
The stronger the IMF, the ___ it is to pull molecules apart.
Harder
Ion-Dipole
Ion & polar molecules
Only for mixtures
Very strong intermolecular attraction
Dipole-Dipole
Two polar molecules or substances
High boilings points
For dipole-dipole, strength depends on ___.
Polarity
More polar (greater difference in electronegativity) means stronger
A larger dipole (MW) in dipole-dipole means …
Stronger attraction
Higher melting point
Higher boiling point
Hydrogen Bonds
H bonds directly to F, O, or N and the bonding atoms have relatively high partial charges
Strong intermolecular force
Overcomes effect of MW
Dipole-Induced Dipole
Polar molecule and non-polar molecule
Only for mixtures
A larger (MW) nonpolar molecule in a dipole-induced dipole leads to…
Stronger induced dipole
Stronger attraction between the pair
More soluble
Larger electron cloud (more squishy)
NO EFFECT ON BOILING/MELTING POINTS
Induced Dipole-Induced Dipole (Dispersion)
Two nonpolar molecules
Weakest IMF
Temporary attractions
Higher MW in dispersion IMF leads to …
More electrons in electron cloud
Stronger dispersion forces between them
Higher boiling/freezing points
More contact
What would be soluble in a polar substance or nonpolar substance?
Polar molecule
Nonpolar molecule
Like dissolves in like
What does vapor pressure mean?
Higher vp means more molecules in gas phase
The weaker the IMF, the higher the vapor pressure
