http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/gam2s2_6.swf
Section 1 – The Gas Laws
1. Use the kinetic-molecular theory
to explain the behavior of gases
2. State, apply, & calculate the 3
following gas laws:
a. Boyle’s Law
b. Charles’s Law
c. Gay-Lussac’s Law
A. The Kinetic-Molecular Theory
1. Gas particles do NOT attract or repel
2. Gas particles are small;
virtually no volume
3. Gas particles are in constant, random
motion
4. Kinetic energy is transferred during
the elastic collisions
5. All gases have same average
kinetic energy at given temp
B. The Nature of Gases
1. Actual gases do not always obey the
kinetic-molecular theory
2. The KMT is based on 4 factors:
a. Temperature (measured in Kelvin)
[oC + 273 = K]
b. Pressure (measured in atm, kPa, etc.)
[1atm = 101.3kPa = 760 mmHg or torr]
c. Volume (measured in liters or mL)
d. Amount of Gas (measured in moles)
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/gaslaw/boyles_law_graph.html
C. Boyle’s Law
1. Temperature held CONSTANT
2. Found inverse relationship
between pressure & volume
3. P1 V1 = P2 V2
Volume –vs- Pressure of a Gas
P1 V1
=
P2 V2
Sample Problem 1:
If the pressure of helium gas in a balloon
has a volume of 4.0 L at 210 kPa, what will
the pressure be at 2.5 L?
340 kPa
Complete Practice Problems:
#1 - #5
SHOW YOUR WORK!!!
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/gaslaw/charles_law.html
http://www.marymount.k12.ny.us/marynet/06stwbwrk/06gas/2slyscharles/2slysflash.html
D. Charles’s Law
1. Pressure held CONSTANT
2. Found direct relationship
between temperature & volume
3.
V 1 = V2
T1
T2
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/gaslaw/charles_law.html
Temperature –vs- Volume of a Gas
V1
=
V2
T1
T2
Sample Problem 2:
A gas sample at 40 oC occupies a volume
of 2.32 L. If the temperature is increased
to 75 oC, what will be the final volume?
2.58 L
Complete Practice Problems:
#6 - #8
SHOW YOUR WORK!!!
http://www.marymount.k12.ny.us/marynet/06stwbwrk/06gas/1amcslussac/amcsgaylussac.html
E. Gay-Lussac’s Law
1. Volume held CONSTANT
2. Found direct relationship
between temperature & pressure
3.
P1
= P2
T1
T2
What would a
graph look like
for Gay-Lussac’s
Law?
P1
T1
=
P2
T2
Sample Problem 3:
The pressure of a gas in a tank is 3.2 atm
at 22 oC. If the temperature rises to 60oC,
what will be the pressure in the tank?
3.6 atm
Complete Practice Problems:
#9 - #11
SHOW YOUR WORK!!!
Section 2 – The Combined Gas
Law & Avogadro’s Principle
1. State, apply, & calculate the
combined gas law
2. Relate number of particles and
volumes using Avogadro’s Principle
A. The Combined Gas Law
1. Amount of Gas held CONSTANT
2.
P1 V1 =
T1
P2 V2
T2
3. This law combines
which 3 laws?
http://kids.earth.nasa.gov/archive/air_pressure/balloon.html
Sample Problem 4:
A gas at 110 kPa and 30 oC fills a
container at 2.0 L. If the temperature
rises to 80oC and the pressure
increases to 440 kPa, what is the new
volume?
0.58 L
Complete Practice Problems:
#12 - #14
SHOW YOUR WORK!!!
B. Avogadro’s Principle
1. Equal volumes of gases at the same
temperature and pressure contains
equal number of particles
2. Molar volume = 22.4 L/mol at STP
3. STP (Standard Temp & Pressure)
Temperature = 0 oC or 273 K
Pressure = 1 atm
Sample Problem 5:
Calculate the volume that 0.881 mol
of a gas at STP will occupy.
19.7 L
Complete Practice Problems:
#15 - #17
SHOW YOUR WORK!!!
Section 3 – The Ideal Gas Law
1. State, apply, & calculate the
ideal gas law
2. State, apply, & calculate Dalton’s
Law of Partial Pressure
3. State, apply, & calculate
Graham’s Law of Effusion
http://www.chemistry.ohio-state.edu/betha/nealGasLaw/fr2.1.html
A. The Ideal Gas Law
1. Contains ALL variables
2. P V = n R T
3. Where
P = pressure (depends on R)
V = volume (liters)
n = amount of gas (moles)
R = ideal gas constant (depends on
pressure)
T = temperature (Kelvin)
R = ideal gas constant (depends on
pressure)
Pressure
R value
atm
0.0821
kPa
8.314
mm Hg
torr
62.4
Sample Problem 6:
Calculate the volume of a gas at STP
with 2.80 moles.
62.8 L
Sample Problem 7:
Calculate the moles of a gas at STP
with a volume of 238 L.
10.6 mol
Sample Problem 8:
Calculate the number of moles of gas
contained in a 3.0 L vessel at 27 oC
with a pressure of 1.50 atm.
0.18 mol
Complete Practice Problems:
#18 - #20
SHOW YOUR WORK!!!
B. Dalton’s Law of Partial Pressure
1. Contains only pressure
2. Where pressure must be in the
same units
3. Ptotal = P1 + P2 + P3 + . . .
4. Sample Problem 9:
If the total pressure of a mixture of oxygen
& nitrogen gases was 820 mmHg, how
much pressure would nitrogen exert if
oxygen had 580 mmHg?
240 mmHg
Complete Practice Problems:
#21 - #22
SHOW YOUR WORK!!!
C. Graham’s Law of Effusion
1. Contains rates & masses of gases
2. Rate A = Mass B
Rate B
Mass A
3. Where
Rate is measured in m/s
Mass is measured in grams
Sample Problem 8:
If neon travels at 400. m/s, estimate
the average speed of butane (C4H10) at
the same temperature.
235 m/s
Sample Problem 9:
Chlorine has a velocity of 0.0380 m/s.
What is the average velocity of sulfur
dioxide under the same conditions?
0.0400 m/s
Complete Practice Problems:
#23 - #24
SHOW YOUR WORK!!!