finals Flashcards
gases tend to have ___
low molecular weight
pressure is the same no matter the ____
element
1 atm = ___ mm Hg = ___ torr = ___ Pa = ___psi
760 mm Hg, 760 torr, 1.01325 x 10^5 Pa, 14.70 Psi
manometer measure the pressure of _____
gas
open ended manometer = ___ , closed ended =___
compare to 1 atm (760 mm Hg), compare to 0 mm Hg
boyles law
volume is inversely proportional to pressure V= 1/p
boyles law math
P1V1=P2V2
Charles law
temp is proportional to volume
Charles law math
V1/T1 = V2/T2
Combined gas law
(P1V1)/T1 = (P2T2)/T2
Gay-Lussac’s law
temp goes down, pressure goes down
Gay-Lussac’s math
P1/T1 = P2/T1
avogandros law
volume is proportional to moles at STP
ideal gas law
Volume is proportional to (moles*temp)/pressure
ideal gas law math
PV=nRT
R in ideal gas law
0.08206 (Latm)/(molK)
density version of PV=nRT
m/V=MP/RT (M=molarity)
Daltons law of partial pressures
IT DOESNT MATTER THE WEIGHT PRESSURE WILL ALWAYS BE THE SAME FOR EACH PARTICLE Ptotal = P1 + p2 + p3 + p4 +……
mole fraction for gases
P1/Pt = (N1RT/V)/(ntRT/V) = N1/Nt
mole fraction
mole of particular gas/total moles of all gas
pressure ratio = _______
= mole ratio
kinetic molecular theory (5)
- gases are in continuous motion
- The volume of the molecules is negligible relative to the total volume in which the gas is contained (FALSE)
- there are no attractive and repulsive forces (FALSE)
- energy can be transferred between molecules during collisions, but average energy does not change.
- the average kinetic energy is proportional to the absolute temperature
average kinetic energy equation
KE=1/2mv^2
lighter gases move ____ and have greater _____ of speed and heavier move ____ and haver less ____ of speed
faster, distribution, slower, distribution
learn about most probable speed, root speed and the other one
on it
u(rms) equation (average kinetic energy of gas)
square root of 3RT/M
R in average kinetic energy of gas
= 8.314 J/molK = (kgm^2/S^2)/mole*K
effusion
escape of gas molecules through a tiny hole into an evactauted space (leaky air tank)
diffusion
gas spreads throughout a space (like febreeze)
mean free path
average distance a gas travels before a collision (pressure increases, distance decreases)
rate of effusion is related to ____
collision rate
Grahams law
R1/R2= square root of Mass2/Mass1 (compares the rate that gases effuse)
deviations from ideal gas happens when _____ and ____
theres high and low pressure
at low temp, you move ____ and have to deal with _____ forces
slower, attractive
van der Waal’s equation for real gases
(P + (n^2a)/V^2)*(V - nb) = nRT
Kinetic molecular theory (KMT) breaks down at ____
high and low pressures
large a in van der Waals=
strong intermolecular forces
large b in van der waals =
larger particle size
b term breaks down _____ in KMT
the second postulate (gas got no volume)
a term breaks down ____ in KMT
the third postulate (intermolular forces dont exist nerd)
what determines matter’s state?
KE (avg) vs Intermolecular forces (IMFs)
liquid has equal ___ and ____
KE and intermolecular forces (almost equal)
gas has more _____ than ____
KE than IMFS
solid has more _____ than ____
IMFs than KE
vander waals paremeters
b = size a =attraction
intramolecular forces vs intermolecular forces
intra = in the same molecule inter = inbetween many molecules
intermolecular forces we care about (4)
- dispersion forces (london dispersion force)
- dipole-dipole interactions
- hydrogen bonding
- ion-dipole interactions
(london) dispersion force (LDFs)
(surface area) instantaneous dipoles lead to attractions between atoms because one electrical imbalance leads to another. MORE surface area MORE LDFs
Dipole-dipole interactions
all molecules have to be polar, positives line up with negatives and higher numbers leads to higher boiling point (bp).
hydrogen bonding
when hydrogen bonds to N, O, or F, and another N, O, or F bonds to the hydrogen (with a lone pair) since the hydrogen has so much unequal positive charge due to the unequal electronegativity. STRONGEST IMF you gonna get
hydrogen bond is ~ _______ of a covalent bond
5-15%
in order to h bond, _____
must have a N,O,F bonded directly to a H
as molar mass goes up, _____
imf goes up due to LDFs (ignoring hydrogen bonding anomaly)
to hydrogen bond, you need a ____
lone pair
tendency for the electron cloud to distort
polarizability
factors of polarizability
- number of electrons
- size of atoms
- shape of molecules
molar mass leads to ____ which leads to ___ which leads to _____ thus ______
more electrons, more LDFs, more IMFs, higher boiling point
weaking to strongest forces
LDFs, Dipole-dipole, hydrogen bonding
Ion-dipole interactions
basically hydrogen bonding but with ions. requires high polar solvent.
low lattice energy leads to _____
easier ion-dipole dissolving
every molecule expierences ______
LDFs (dispersion forces)
viscosity =
the resistance to flow
higher IMF = ______ in fluids
Higher viscosity
surface tension
guys near the surface of water are more densely packed than guys at the bottom due to IMFs pulling the surface downward.
Cohesion
IMF’s that bond a material to itself (water to water)
adhesion
IMF’s that bond a material to other materials (water to a towel)
capillary action
basically using stronger IMF’s to move liquids like water. can be done in reverse like in mercury
why do we have a menescus in water?
because waters adhesive force to glass is stronger than its cohesive force to itself
vapor pressure
the pressure vapor exerts at equilibrium
boiling point
temperature at which the vapor pressure becomes more powerful than the surrounding pressure.
in order to escape the liquid phase, you need to overcome _____
IMFs
normal boiling point
the boiling point at 1 atm for a liquid
lower vapor pressure for chemicals with _____
higher IMFs
volatile
evaporate easily
critical point
the point where you go past the normal graph and become supercritical
triple point
where you are all three phases at once
supercritical fluids
behaves kinda like a fluid and a gas at the same time
memorize and draw phase diagram in slides
oki
crystalline
highly ordered
amorphous
lack of order
metallic solids
held together by a “sea” of electrons, not brittle (metals)
Ionic Solids
salts, cations and anions bonded together, brittle DO NOT CONDUCT ELECTRICITY AS A SOLID
covalent-network solids
diamond, SUPER strong,
molecular solids
held together with IMFs, not very strong, WEAKEST
memorize the solids slide
oki doki
polymers
long chains of covalent bonds
nanomaterials
crystalline compounds the sizer of 1-100 nm
