Polarity and IMF Flashcards
Intermolecular forces:
between molecules
Intramolecular forces:
covalent bonds btwn atoms
Which one is stringer inter or intramolecular forces?
Intra
Molecular polarity:
polar bonds are formed when there is an unequal sharing of e- btwn atoms
Molecular polarity of molecules influences the…
forces btwn molecules
Why is it important to know the polarity of a molecule?
properties of subtances (boiling point and solubility) are affected by the forces btwn the molecules of a substance
Dipoles:
polar molecules
Dipole moment:
arrow used to show the direction of polarity and points towards more electronegative atom (tail crossed on the more + end)
Nonpolar molecules do not…
create poles bc equal sharing of e-
Polar molecules are :
asymmetrical
Nonpolar molecules are;
symmetrical
In a nonpolar molecule the forces….
cancel out and net dipole moment is zero
Molecular polarity depends on:
-polarity of the bonds
-the shape of the molecule
Determining molecular polarity:
- draw lewis structure of molecule
- determine polarity of the bonds
two or more lines of symmetry in molecule=
nonpolar
zero or one line of symmetry=
polar
Molecular polarity is determined by:
shape and distribution of charge in the molecule
SNAP:
Aymmetrical Nonpolar Asymmetrical Polar
If atoms in the molecule are symmetrical=
charges are balanced by each other (nonpolar)
Intermolecular forces together are called:
Van der Waals Forces
Van der Waals Forces:
-London Dispersion Forces
-Dipole-Dipole Force
-Hydrogen Bond
The boiling point of a liquid is determine by the…
strength of its intermolecular forces
Stronger intermolecular forces=
higher boiling point
Intermolecular forces vary in strength and are weaker than
covalent intramolecular forces
Intermolecular forces : weakest to strongest
London Dispersion Forces
Dipole-Dipole force
Hydrogen Bond
(London Dispersion Forces) E- are in
constant motion and distribution may be uneven
(London Dispersion forces) uneven e- distribution creates a…
temporary + and - pole
(london dispersion force) Temporary dipole can->
induce a dipole in a nearby atom
London Dispersion forces:
intermolecular forces created by the constant motion of e- and temporary dipoles
(london dispersion forces) Induced dipoles account for the fact that a nonpolar molecule like oxygen is able to ->
dissolve in water - a polar molecule
Dipole-Dipole forces:
the force of attraction between polar molecules (dipole and dipole)
Dipole-dipole forces are _____ than London Dispersion forces
stronger
Hydrogen bond:
a special type of dipole- dipole force
(hydrogen bond) Special type of dipole- dipole force occurs when:
hydrogen bonds with N,O, or F
The strength of the hydrogen increases w/:
the degree of electronegativity of the atom bonded to it
