Unit 1 (ch 6,10,11) Flashcards
Characteristics of gas phase
- no defined shape or volume
- compressible
- change volume with temp
- miscible
- less dense
Atmospheric pressure
1 ATM=
P ATM = force/area
1 ATM= 760 mmhg
1 ATM = how many pascals
101,325
What happens if area decreases?
Pressure increases
Boyles law
Related to pressure and volume
P = 1/V
PV= constant
P1V1=P2V2
pressure increases, volume decreases
Charles law
Related to volume and temperature
V=T
V1/T1= V2/T2
*volume increases, temperature increases
Avogadro’s law
Related to volume and number of moles
V1/n1= V2/n2
*as volume increases, number of moles increases
Amontons law
Related to pressure and temperature
P1/T1 = P2/T2
as pressure increases, temperature increases
Ideal gas law
PV=nRT
P1V1/n1T1 = P2V2/n2T2
Standard temp
0 degrees C
Standard pressure
1 bar/1atm
Standard volume
22.4 L/mol
Does gas have a greater density or less density than other forms of matter?
less
at STP density =
molar mass/molar volume
density in relation to PV=nRT
PM/RT = m/v = d (M= molar mass, m = mass)
Given that density of gases depends on their molar mass, which is the least dense?
Cl2, He, H2, N2
H2- least molar mass
highest molecular weight = most or least dense?
most
increase temperature, density (blank)
decreases
decrease temperature, density (blank)
increases
Dalton’s law of partial pressures
Ptot = P1 + P2 + P3…
mole fraction
moles of one element/total moles of all elements
Partial pressure of a gas =
mole fraction x Ptotal
Kinetic molecular theory of gases list
1) gas molecules are tiny compared to the volume they occupy
2) move constantly and randomly
3) motion associated with average KE (same temp= same KE)
4) collisions with other molecules and walls of container are elastic (T and V constant)
5) assume no attraction or repulsion between gas molecules
with gases, smaller V means (blank) collisions and (blank) pressure
increase, increase
More molecules means (blank) collisions and (blank) pressure
increase, increase
Higher temperature means (blank) collisions and (blank) pressure
increase, increase
Molecular speed and kinetic energy
KE = 1/2 mu^2
Three important values
- Um
- Uavg
- Urms
(most common speed)
(average speed)
(root mean square speed)
larger gas moves faster or slower?
slower
KE avg is the same for different gases at the same (blank)
temperature
Graham’s law is related to
effusion and diffusion
Van der Waal’s equation
(P + n^2a/v^2) x (v-nb) = nRT
solids have (blank) interparticle forces KE (blank) attraction
strong,
liquids have (blank) interparticle forces KE (blank) attraction
medium, >
gases have (blank) interparticle forces KE (blank) attraction
weak,»_space;
strong forces = solid with (blank) boiling point
high
weak forces = gas with (blank) boiling point
low
ion-ion interactions
ionic compounds
strongest
E = (blank)/(blank)
E = (Q1Q2)/d (smaller distance = stronger)
stronger interactions with (blank) distance
smaller
Interactions between polar molecules include and they relate to differences in (blank)
ELECTRONEGATIVITY
- ion-diple
- diploe-diple
- —hydrogen
ion-dipole interactions
ions and polarized molecules
ex) water and salt
Dipole-Dipole
weaker, less organized
Hydrogen
special type of dipole-dipole
O-H, N-H, or F-H
H bonded to highly electronegative element
increase boiling point
Dispersion forces
london dispersion, induced-dipole induced dipole
occur between all molecules
weakest
change in electron distribution
larger molecules = more force (more polarized)
Which is the most polarizable? I2, Br2, Cl2, F2
I2
Why do strenghts of London forces increase with size?
larger molecules have more electrons and therefore, more distortions and a bigger force
-nonpolar liquid (oil)= high boiling
Van der Waals forces
non-ideal gases
(P + n^2a/v^2)(v-nb)=nRT
Thinking about the factors that influence Van der Waals constants, which do you expect to have the larges a constant? He, H2O, N2, NO
H2O
key point with polarity and solubility
LIKE DISSOLVES LIKE
O2 has (blank) solubility in H2O
limited
increase temp, (blank) gas solubility
decrease
fish example
O2 less soluble with heat, fish die in warm water
low pressure (high elevation) = (blank) gas solubility
lower
Henry’s law
Cgas= KH-Pgas
concentration, constant, partial pressure
hydrophobic vs hydrophillic
fearing vs loving
what two things influence the phase of matter?
temperature and pressure
solid CO2 =
dry ice
qualities of water
higher melting and boiling point
forms strong H-bonds
surface tension
cohesive forces
molecules sticking together
adhesive forces
molecules sticking to other things
stronger forces = (blank) viscous
more
pentane vs car oil- which is more viscous
car oil
What is more viscous, freshwater or seawater?
seawater
cold water = (blank) dense
most
solvent dissolves (blank)
solute
breaking bonds example
NaCl (ionic)
making bonds example
NaCl in H2O (ion-dipole)
delta H solution =
delta H ion-ion + delta H dipole-dipole + delta H ion-dipole
delta H solution = break + make
delta H ion-ion (break) + delta H hydration (make)
lattice energy
U = K (Q1Q2)/d
-more negative U is harder to dissolve
lattice energy trend
smaller ion (top right)= larger negative energy
which has a higher lattice energy RbF or LiF?
LiF
Born-Haber cycle
series of chemical steps to make ionic solid from elements
delta H solution = delta H hydration (+ or -? U)
-
rate of vaporization depends on
pressure, temp, surface area, strength of intermolecular forces
temperature increases, vapor pressure (blank)
increases
delta H hydration for H2O is positive or negative?
negative
in general, if solute is nonvolatile, vapor pressure (blank)
decreases
nonvolatile examples
sugar and salt