Chapter 6: Gases Flashcards
volume of a gas equal the volume of its BLANK
container
gases have neither fixed BLANK nor BLANK
shape or volume
all gases form BLANK mixtures
homogeneous
describe level of interaction of gas molecules
gas molecules have little interaction, they are relatively far apart from each other
formula for gas pressure
force dvided by area
in a liquid, gases occupy how much of the space
70%
what does STP stand for
Standard Atmospheric Pressure
1 atm equals how many mmHg/Torr
760 mmHg and 760 Torr
how are volume and pressue related in gas laws
inversely related
what is Boyle’s Law
gas volume is inversely proportional to pressure
Boyle’s law formula
V1P1=V2P2
what is Charles’s Law
gas volume is directly proportional to Kelvin temperature
Charles’s Law formula
V1/T1=V2/T2
Avogadro’s Law
voume of gas is proportional to molar amount
Avogadro’s Law formula
V1/n1=V2/n2
what is the gas constant in IGL
r = .08206 Latm/molk
IGL standard temperature for gas
t= 0° C
standard pressure for gas IGL
P = 1 atm
IGL for volume
Liters
IGL unit for pressure
atm
IGL unit for temperature
Kelvin
what is molar volume of a gas in IGL
V = 22.414 L for 1 mole of an ideal gas at STP
Dalton’s Law
total pressure of the gas mixture equals the sum of partial pressure of the individual gasses in the mixture
Dalton’s Law formula
P(total) = P(A) + P(B) + P(C)…
IGL equation
PV = nRT
mole fraction equation
X(A) = P(A)/P(total)
what does KMT stand for
kinetic molecular theory
what is KMT
model that explains behavior of gases
In KMT, gas consists of particles in what kind of motion
constant, random motion
In KMT, the size of gas particles is BLANK compared to the size of container
the size is negligible
In KMT, the strength of intermolecular forces is BLANK
negligible
In KMT, the average KE of gas particles is directly proportional to what?
Kelving temperature
In KMT, all collisions of the gas particles are BLANK. What does this mean?
Alll collisions are elastic, meaning there is no loss of KE
A real gas will have properties most like an idea gas at what temperature and pressure?
high temperature and low pressure
real gases differ from idea gases in that…
real gases have volume and particles that interact and collide
speed at which a molecules is traveling depends on what two things?
speed depends on mass of the molecule and temperature
the lighter a gas particle, the BLANK the speed
faster the gase’s speed
formula for rms speed
u = √3RT / √M
what is effusion
escape of gas through a tiny orifice into an evacuated chamber
what is Graham’s Law of effusion
rate of effusion is inversely proportional to the square root of the molar mass
what is diffusion
the mixing of two gases, from higher concentration to lower concentration
what is effusion rate?
the faster the particles move, the more likely they are to pass through the effusion orifice
deviations from idea gas behavior are largest when pressure is BLANK and temperature is BLANK
when pressure is high and temperature is low
when pressure is high, size becomes BLANK
significant
when temperature is low, attractive forces become BLANK
significant
what does “n” equal?
amount of gas in moles
in a J-tube, the height of Hg is proportional to what?
the pressure of the gas
define molar volume
volume occupied by 1 mole of a substance at T=0° C / 273.15 K and P=1atm
define pressure
amount of force per unit area
relationship between concentration and pressure
direct relationship: lower concentration=lower pressure
what is pressure measured with
barometer
what is atmospheric pressure
average pressure at sea level
what do simple gas laws describe
relationship between P, V, T, and n
what does extrapolate mean
to extend
what did Charles quantify?
relationship between volume and temperature
what happens to speed of particles when temperature increases?
particles move faster
the molar volume of a gas of 22.414 L only applies at what?
standard temperature and pressure
density of a gas equals
molar mass divided by molar volume
formula for molar gas
molar mass = mass/moles
describe the interaction of molecules in an ideal gas
molecules in an IG do not interact
general gas law formula
P1V1/T1 = P2V2/T2
one mole of an ideal gas at STP has a volume of what?
22.414 L
according to KMT, when gas density is very low…
particles are far apart
the IGL are most valid when…
when particle density is very low
when particle density is very low…
the distance between particles is greater than the particle size
describe kinetic energy at high temperatures
kinetic energy or particles is much greater than the strength of intermolecular forces
what is assumed of gas particles when kinetic energy is very high
it is assumed that gas particles don’t interact, other than random collisions
describe the distance of gas particles at low pressures
gas particles are far away from each other
when gas particles are far away from each other, what is assumed?
the size of gas particles is negligible
observations lead to what?
laws
what does kinetic molecule theory do for gas laws
KMT provides reasons behind the laws
what is a gas
collection of particles in constant motion
when particle size is negligibly small, what can be said of volume?
the particles don’t occupy volume
average kinetic energy depends ONLY on what?
temperature of gas
Can the speed of a GIVEN molecule in a gas double at constant temperature? Explain your answer.
Yes. At any given instant, there are a range of values of molecular speeds in a sample of gas. Any single molecule can speed up or slow down as it collides with other molecules. The average velocity of all the molecules is constant at constant temperature.
Describe what happens to the average kinetic energy of ideal gas molecules when the pressure of the gas is increased by reducing the volume at constant temperature.
average kinetic energy with remain constant due to constant temperature
Describe what happens to the average kinetic energy of ideal gas molecules when the pressure of the gas is increased by increasing the temperature at constant volume.
Av. KE will increase because temperature increased
Describe what happens to the average kinetic energy of ideal gas molecules when the average velocity of the molecules is increased by a factor of 2.
the kinetic energy will increase by a factor of 4 because velocity is squared in the equation for KE
relationship between temperature, average KE, and average velocity
as temperature increases, so does KE and velocity
Kinetic eneregy is also known as what kind of energy
thermal energy
what does elastic mean when discussing collision of particles
when two particles collide, energy is exchanged, but there is no overall loss or gain of energy
how is rate of effusion related to mass, speed?
rate of effusion is inversely related to mass, but directly related to speed
describe the relationship between KE and pressure
pressure is proportional to average KE
formula for kinetic energy
KE(ave) = 1/2m * v^2(ave)