Ch 11 - IMFs Flashcards
Intermolecular Force
attractive forces between all molecules and atoms.
High thermal energy
tend to be gasses
low thermal energy
tend to be solids or liquids
What has the strongest IMFs?
Solids, then liquids, then gasses
Crystalline Solid
the atoms or molecules are arranged in a well-ordered three-dimensional array
Amorphous Solid
the atoms or molecules have no long range order
How do you change the state of matter?
Increase temperature and/or pressure.
Higher pressure =
more dense state
Higher temperature =
less dense state
4 types of IMFs
dispersion force, dipole-dipole force, hydrogen bond, and ion-dipole force
Dispersion Force
london dispersion force.
all molecules and atoms have these.
fleeting charges create an unbalance of electrons around the atoms/molecules creating temporary dipoles.
What can dispersion forces do?
the temporary +/- in one can trigger a chain reaction in others creating strength temporarily.
Major factors affecting dispersion forces?
the larger the electron cloud the greater the dispersion forces can be.
All other things being equal then larger molar mass = larger dispersion force.
Shape also plays an important factor: more surface area = more dispersion forces.
Greater dispersion force =
higher boiling point.
more energy is required to break the bonds.
Why does shape affect LDFs?
long chains have greater LDFs than clumped patterns because more surface area = chance to tangle and increase attraction.
all other factors = then longer chain = more LDFs
C6H14>C5H12
Dipole-dipole Force
exist in all molecules that are polar.
Has permanent dipole - a molecule with an electron rich and electron poor regions
Permanent Dipole
a molecule with an electron rich and electron poor regions
Dipole-Dipole Forces still have _____.
Dispersion forces
Dipole-Dipole Forces have higher ______
melting and boiling points than molecules with similar masses because there are more forces to overcome.
A greater dipole moment typically_____.
has a higher boiling point when compared to non dipole-dipole force molecules of similar molar mass.
Miscibility
the ability to mix without separating into two states of liquids.
polar with polar.
nonpolar with nonpolar.
Hydrogen Bonding
incredibly strong type of Dipole-Dipole Force caused by very large electronegativity difference AND close proximity to H since it only has 1 electron.
H with FON
Hydrogen bonding is the _____.
strongest of LDFs, Dipole-Dipole, and H Bonds because it has all 3 types.
Unique.
Ion-dipole Force
an ionic compound mixed with a polar compound.
Especially important with aqueous solutions.
Very strong compared to other IMFs.