Exam 1 Flashcards
only compressible state of matter
gas
specific volume, but fill container
liquids
only state of matter that cannot diffuse
solids
specific shape & volume
solids
no specific volume - fills container
gases
3 things that cause change in state of matter
temperature
pressure
charge
determines state of matter
IMFs
define IMFs
short range attractive & repulsive forces between molecules
4 types of IMFs
- dipole-dipole interactions
- dispersion forces
- hydrogen bonds
- ion-dipole interactions
only non-van der waals IMF
ion-dipole
explain dipole-dipole
polar molecules - polarity caused by differences in electronegativity among atoms in molecule
partial charges result in a dipole
+ parts of molecule attracted to - parts of other molecules
examples of dipole dipole
H2O
HF
HCl
most electronegative parts of PT
top right
H
most electronegative element (4)
fluorine
____ and _____ of dipole dipole interactions determines properties
strength and number
strength of IMFs is reflected in….
BP
describe hydrogen bonding
subset of dipole-dipole interactions
includes H bound to N, O, or F
when H is bound to highly electronegative atoms, it acquires a highly positive charge & attracts other electronegative atoms
explain dispersion forces
result from instantaneous dipoles & induced dipoles
occur among ALL molecules
constantly happening
describe instantaneous dipole
nonuniform distribution of electrons (even in a nonpolar molecule)
temporary, moves back and forth
describe induced dipole
when an instantaneous dipole polarizes neighboring molecules
“pushes” electrons
_____ and _____ determines magnitude of dispersion forces
size & shape
which shape creates greater dispersion forces?
linear
more surface area
which molecules have largest instantaneous dipoles?
large
nonpolar
describe ion-dipole interactions
ions interacting with neutral polar molecules
examples of ion-dipole
salt dissolving in water (Na+ becomes surrounded by the O side of the water molecule, Cl- becomes surrounded by the H sides of the water molecule)
ammonia
acetic acid
magnitude of ion-dipole interactions depends on…
charge & size of ion
strongest ion-dipole interactions involve…
cations
highly charged ions
ions with smaller radii
define viscosity
resistance to flow
what increases viscosity?
IMFs
larger surface area
lower temp
higher molecular weight