Class Three Flashcards
key property of a physical change
no intramolecular bonds are broken - only affects intermolecular forces
temperature is a measure of the amount of internal ___ energy
kinetic
kinetic energy of molecules directly affects its ____
phase
the higher the average kinetic energy..
the higher its entropy
fusion phase change
solid → liquid
fusion phase change
solid → liquid
crystallization phase change
liquid → solid
sublimation phase change
solid → gas
deposition phase change
gas → solid
heat of transition
amount of energy required to complete a phase transition
heat of transition formula
q = n x change in H
1 cal =
4.2 J
when a substance absorbs or releases heat, 1 of 2 things can occur..
either temperature changes OR it will undergo a phase change
heat capacity formula
q = mc(change in T)
what is a substance’s specific heat
intrinsic property → tells us how resistant it is to changing temperature
during a phase transition.. (temp)
the temperature of the substance does not change
during a phase transition.. (temp)
the temperature of the substance does not change
triple point
the temperature & pressure at which all 3 phases exist in equilibrium
critical point
marks the end of the liquid-gas boundary
after this, substances display properties of liquids & gases aka supercritical fluid
what makes water special
denser in liquid form vs solid
increasing pressure on ice..
turns into liquid (ice skating)
what is vapour pressure
force exerted by the gas particles
boiling point is when..
vapour pressure = atmospheric pressure
why do the molecules of gas essentially take up no colume
they’re so small compared to the space in between them
what defines the pressure of a gas
the collisions of the molecules with the walls of the container
kelvin to celsius
C + 273 = K
pascal to atm
100 kPa = 1 atm
atm to torr
1 atm = 760 torr
ideal gas law formula
PV = nRT
Charle’s law
if pressure is constant, gas will expand when heated & contract when cooled
volume is proportional to temperature
Boyle’s law
if temperature is constant, as volume decreases → pressure increases
volume and pressure are inversely related
combined gas law formula
Avogadro’s Law
equal pressure, volume and temp = then the two have the same # of particles
main assumptions for kinetic-molecular theory (2)
particles of an ideal gas experience no intermolecular forces
volume of individual particles of an ideal gas can be ignored compared to the volume of the gas container
what equation is used for real gases (do not behave as ideal gases)
van der Waals equation
van der Waals formula
when does the deviation from ideal gas law become more pronounced
with gases with stronger intermolecular forces
what makes a good ideal gas
low molecular weight & weak intermolecular forces
Dalton’s law of partial pressures
total pressure is the sum of partial pressures of all the gases in a mixture
what is effusion
the escape of a gas molecule through a tiny hole
Graham’s law of effusion
where r = rate of effusion
and M = molar mass
what is rms
average speed of molecules
avg kinetic energy and temp relationship
they are directly proportional
the solvent is usually..
water
what is a strong electrolyte
something that will dissociate 100%
van’t Hoff factor
number of particles produced in a solution per mole of substance
how do electrolytes dissociate into water
agitation (endo) → dissociation (endo) → solvation (exo)
how do polar non-electrolytes dissociate in water
agitation → solvation
how do non-polar non electrolytes dissociate in water
it doesn’t lol
unsaturated solution
concentration is less than solubility
saturated solution
concentration = solubility
supersaturated solution
concentration is greater than solubility
when is solubility indirectly proportional to temp
gas solutes in water
always soluble electrolytes in water
group 1 ions, H+, NH+. NO3-
not soluble electrolytes in water
transition metals
PO4-
