Studied by 3 peoplekinetic theory
all matter consists of tiny particles that are in constant motion
elastic collisions
A collision in which no kinetic energy is lost; gas particles have same speed before and after the collision
hydrogen bonding
strong type of intermolecular dipole-dipole attraction that occurs between hydrogen and F, O or N
london dispersion forces
the intermolecular attraction resulting from the uneven distribution of electrons and the creation of temporary dipoles
dipole-dipole forces
intermolecular forces that exist between polar molecules, the strength of intermolecular attractions increase when polarity increases
translational motion
movement in which an entire molecule moves in a definite direction (gas)
vibrational motion
periodic motion of atoms within a molecule (solids)
rotational motion
motion of a body that spins about an axis (liquids)
compressibility
a measure of how much the volume of matter decreases under pressure
difussion
movement from an area of higher concentration to an area of lower concentration
effusion
a process by which gas particles pass through a tiny opening
pressure
force per unit area
manometer
instrument that measures pressure
barometer
instrument that measures atmospheric pressure
temperature
a measure of how hot or cold something is
vacuum
a space where no particles of matter exist
phase diagram
a graph showing the conditions at which a substance exists as a solid, liquid, or vapor
triple point
the temperature and pressure conditions at which the solid, liquid, and gaseous phases of a substance coexist at equilibrium
position of particles in a liquid [are fixed/can vary]
can vary
total volume of a liquid is [fixed/variable]
fixed
why is the density of a liquid higher than that of a gas of the same substance?
because of the intermolecular forces that hold liquid particles together
liquids are considered to be [incompressible/compressible]
incompressible, because particles are already tightly packed
viscosity
a liquid's resistance to flow (thickness)
stronger intermolecular forces result in [higher/lower] viscosity
higher, due to strong bonds
bigger particle size and shape result in [higher/lower] viscosity
higher, because big particles move more slowly
higher temperature results in [higher/lower] viscosity
lower (indirect relationship), think oil spreads faster on a pan when it is heated, or cold maple syrup travels slower than warm
surface tension
the energy required to increase the surface area of a liquid by a given amount
why is water's surface tension so high?
because water has hydrogen bonds, which causes strong intermolecular forces
surfractant
any substance that interferes with the hydrogen bonding between water molecules and thereby reduces surface tension
cohesion
attraction between molecules of the same substance
adhesion
attraction between molecules of different substances
crystalline solid
a solid whose atoms, ions, or molecules are arranged in an orderly, geometric structure
lattice
regular arrangement of particles
unit cell
the smallest group of particles within a crystal that retains the geometric shape of the crystal
allotrope
an element with different forms with different molecular structures (ex. carbon)
ionic solid
solid composed of positive and negative ions held together by strong electrostatic attractions
hard, brittle, high melting point, poor conductivity
ex. NaCl, KBr, CaCO3
molecular solid
a solid composed of neutral molecules at the lattice points
soft, low to moderately high melting point, poor conductivity
ex. I2, H2O, NH3, CO2, C12H22O11
covalent network solid
a solid that consists of atoms held together in large networks or chains by covalent bonds
very hard, very high melting point, often poor conductivity
ex. diamond and quartz
metallic solid
solid composed of metal atoms surrounded by mobile valence electrons
soft to hard, low to high melting point, malleable or ductile, good conductivity
ex. all metallic elements
amorphous solid
a solid made up of particles that are not arranged in a regular pattern
ex. glass, rubber, plastics
5 differences between amorphous and crystalline solids
amorphous solids lack a definite geometric shape
unclean cleavage when cut
isotropic (physical properties are the same in all directions)
non-definite melting point
non-definite heat of fusion
evaporation
when vaporization occurs only at the surface of a liquid
doesn't require liquid to be above boiling point
can occur from collision of air particles
vaporization
the change of state from a liquid to a gas
occurs when liquid is above boiling point
dynamic equilibrium
when the rate of evaporation is equal to the rate of condensation
vapor pressure
the pressure exerted by a vapor over a liquid in dynamic equilibrium
volatility
the tendency of a substance to vaporize
substances with high vapor pressures are [more/less] volatile
more because there are less intermolecular forces
substances with low vapor pressures are [more/less] volatile
less because there are less intermolecular forces
IMFs and vapor pressure have a [direct/indirect] relationship
indirect, as IMFs increase, vapor pressure decreases
(because higher IMFs means higher boiling point)
boiling point and vapor pressure have a [direct/indirect] relationship
indirect, as boiling point increases, vapor pressure decreases (because less vapor pressure makes a substance difficult to boil)
temperature and vapor pressure have a [direct/indirect] relationship
indirect, related to boiling point. lower boiling point means lower IMFs, so vapor pressure increases and the substance is more volatile
normal boiling point
the boiling point of a liquid at a pressure of 1 atm
critical point
the temperature and pressure at which the gas and liquid states of a substance become identical and form one phase
volume (v) and gas pressure have a [direct/indirect] relationship
indirect, as one increases the other decreases
temperature (T) and gas pressure have a [direct/indirect] relationship
direct, as one increases so does the other
amount of gas (n) and gas pressure have a [direct/indirect] relationship
direct, as one increases so does the other
boyle's law
P1V1=P2V2
T and n are constant
isothermal system
charles' law
V1/T1=V2/T2
P and n are constant
isobaric system
gay-lussac's law
P1/T1=P2/T2
V and n are constant
isochoric system
combined law
P1V1/T1=P2V2/T2
n is constant
avogadro's law
V1/n1=V2/n2
T and P are constant
isothermal and isobaric system
ideal gas law
PV=nRT
using ideal gas law to determine molar mass
M = mRT/PV
(m is in g)
using ideal gas law to determine density
p = MP/RT
graham's law of effusion
rate A/rate B = square root of Mb/Ma
dalton's law of partial pressures
states that the total pressure of a mixture of gases is equal to the sum of the pressures of all the gases in the mixture
Ptotal = P1 + P2 + P3...
Note
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