Studied by 21 people"you have mass so you matter" - steward
welcome back.
let’s play a game of “some, none, or all” (flip me!)
i give you a statement, you tell me if that statement is true for all, some, or no gases
gases are matter
all
gases are flammable
some
gases are visible
some
gases react
some (REMEMBER: noble gases!)
yay you did it! next section
hi
true or false: gases weigh differently depending on their molar mass
true!
how do gases move?
process called diffusion
gas moves from high to low concentration
ie: when you burn a candle you can smell it
why do gases move at different speeds?
the more weight, the slower the gas is
or vice versa, the less it weighs the speedier it is
what is the law that relates the speed of gases to their molar mass?
graham’s law
what are the four parts of kinetic molecular theory
gases…
are made of tiny particles, travelling in straight lines
do not occupy volume
collisions between molecules are perfectly elastic
no attractive or repulsive forces between the particles
temperature
measure of kinetic energy
volume
amount of space an object occupies
what determines volume for gases?
size of container
pressure
force of gas particles hitting the container
if particles are rapidly and frequently hitting the sides of the container, would the pressure be higher or lower?
higher
how does area affect pressure?
higher area → lower pressure
lower area → higher pressure
magic.
what is STP?
Standard Temperature & Pressure
pressure → 1 atm
temperature → 273 K
now we get into the actual gas laws :D
yay
Dalton’s Law, what’s the tea?
Dalton’s Law - Partial Pressure
the total pressure of a gas mixture = the sum of the different gas components
not dependent on the weight of the gas, only the amount (it’s why we use moles!)
Example Problem: A mixture of 4.5% H2, 76% O2, and 19.5% N2 has a total pressure of 2.3 atm. What is the partial pressure of each of the gases?
PH2= 0.10 atm; PO2 1.75 atm; PN2= 0.45 atm
Next: Boyle’s Law
Boyle’s Law
changes pressure and volume
when moles and temperature are constant, presuure and volume have an inverse relationship
when one goes up, other goes down, and vice versa
what kind of container would gas have to be in to undergo Boyle’s Law?
flexible container (like a balloon) because the volume is changing
Example Problem: a gas occupies 1.65L at 1.00 atm what will be the new volume if the pressure becomes 3.00 atm?
0.520L
Charles’ Law
Charles’ Law
V1/T1=V2/T2
V and T change, directly related
n and P are constant
Example Problem: When 10.5 L of gas at 20C is heated, the volume increases to 21 L. What is the new temperature in Celsius? Assume no other changes in the gas.
313 C
Gay-Lussac’s Law
Gay-Lussac’s Law
P1/T1=P2/T2
P and T change, directly related
n and V constant
When a gas has a pressure of 500 mmHg at 25C and is expanded to standard pressure, what happens to the temperature?
The temperature would rise to 452.96 K because the pressure and temperature are directly related
Combined Gas Law
Combined Gas Law
P1V1/T1 = P2V2/T2
amount of gas (moles) is the only constant
Ideal Gas Law
PV=nRT
predicts behavior of gas
used to find one missing variable when you have the other three
what does the “R” stand for?
“R” → universal gas constant
0.0821 (atm x L)/(K x mol)
what is the formula(s) to find molar mass?
M=m/n
M → Molar Mass
m → mass
n → mols
M=dRT/P
how do you find density?
d=m/v
Note
Flashcard