Transcript Gas Law Vocabulary - Pre

Gas Laws
Pressure
• The force per unit area on a surface
• Standard Pressure = 1 atmosphere
(atm.)
• Conversions:
– 1 atmospheres (atm)
– 760 millimeters of Mercury (mmHg)
– 760 Torricelli's (torr)
– 1.01 x 105 Pascals (Pa)
– 14.7 pounds per square inch (psi)
Conversion Practice
• Pressure
1) 350 mmHg = __________ psi
2) 345 Pa = ____________ mmHg
3) 1.2 atm = __________ torr
Temperature
• Average kinetic energy of the
particles in a sample of matter
(***ALL TEMPERATURES MUST BE
CONVERTED TO KELVIN***)
• Standard Temp. = 0 0C or 273 K
• Conversions:
o Kelvin = 0C + 273
o Celsius = K – 273
Conversion Practice
• Temperature
1) 26 0C = _______ K
2) 70 0C = _______ K
3) 456 K = _______ 0C
Volume
• The amount of space occupied by an
object
• Conversions:
o 1 L = 1000 mL
Boyle’s Law
• The volume of a fixed mass of gas
varies inversely with pressure at a
constant temperature
• Formula: (P1)(V1) = (P2)(V2)
Charles’ Law
• The volume of a fixed mass of gas
at constant pressure varies directly
with the temperature
• Formula: V1 = V2
T1
T2
or V1T2 = V2T1
Boyle’s and Charles
1) How hot will a 2.3 L balloon have to
get to expand to a volume of 400 L?
Assume that the initial temperature
of the balloon is 25 0C.
2) 1.00 L of a gas at standard pressure
is compressed to 473 mL. What is
the new pressure of the gas?
Boyle’s and Charles
3) Helium occupies 3.8 L at -45°C.
What volume will it occupy at 45°C?
4) Ammonia gas occupies a volume of
450 mL at 720 mm Hg. What
volume will it occupy at standard
pressure?
Combined Gas Law
• Relationship between the pressure,
volume, temperature, and number of
moles of a fixed amount of gas
• Formula: P1V1 = P2V2
T1
T2
Combined Gas Law Practice
1. If I initially have a gas at a pressure of 12 atm, a
volume of 23 liters, and a temperature of -73 0C,
and then I raise the pressure to 1418.2 kPa and
increase the temperature to 27 0C, what is the
new volume of the gas?
2. A gas takes up a volume of 17 liters,
and is placed at STP. If I raise the
temperature to 77 0C and lower the
volume to 9 liters, what is the new
pressure of the gas?
Avogadro’s Law
• Equal volumes of gases at the same
temperature and pressure have the
same number of molecules
• Formula: V1 = V2
n1
n2
Avogadro Practice
• A sample of N2 has 1.70 moles and
occupies 3.80 L at 25.0˚C.
– What volume will it occupy with 2.60
moles?
– How many moles are in a sample that
occupies 1.45 L?
Ideal Gas Law
• An imaginary gas that perfectly fits
all the assumptions of the kinetic
molecular theory
•
Kinetic
Molecular
Theory
A theory based on the idea that gases are always
in motion
• Assumptions:
1. Gas particles are in constant motion
2. The average kinetic energy of gas particles
depends on the temperature of the gas
3. Gases consist of large numbers of tiny particles
spread far apart
4. Collisions between gas particles are elastic
collisions
5. There are no forces of attraction or repulsion
between gas particles
Ideal Gas Law Cont’d
• Formula:
PV = nRT
• Parts of the Equation:
– P = Pressure must be in unit that
matches R
– V = Volume must be in Liters
– n = number of moles must be in Moles
– R = ideal gas constant
– T = Temperature must be in Kelvin
Ideal Gas Law Practice
1) If I have an unknown quantity of
gas held at a temperature of 922 0C
in a container with a volume of 25
mL and a pressure of 560 atm, how
many moles of gas do I have?
Ideal Gas Law Practice
2) At what temperature would 2.10
moles of N2 gas have a pressure of
950 mm Hg and in a 25.0 L?
Starter (The faster you do this the
better your day will become!!!)
1) Get out your homework and KEEP it
on your desk!
2) Get out your lab notebook.
3) Have a calculator and something to
write with.
(MW)PV = gRT
• If you had 14 liters of propane
(C3H8) under 3.7 atmospheres of
pressure, being stored at 50 degrees
Celsius, how many grams of propane
would you have?
(MW)PV = gRT
• If you had 7.2 grams of Hydrogen
being stored at -25 degrees Celsius,
under 2.4 atmospheres of pressure,
what would the volume of the
container be?
(MW)PV = gRT
• A 540 ml Frito bag contains 40
grams of an inert gas. If its
molecular weight is 2.02 g/mol and
the temperature is 48oC, what is the
pressure in atm?
(MW)P = DRT
• A group of scientist discovered a new
gas. The gas is being stored in a
container that is at 412 K, and 3.5
atmospheres of pressure. The gas
they learn has a density of 2.8 g/L.
What is the molecular weight of the
gas?
(MW)P = DRT
• Radon has a density of 8.75 g/L
when it is at 54oC. What pressure is
on the gas in p.s.i.?
(MW)P = DRT
• Suppose that you found a new
molecule known as the Cannonium.
Cannonium has a molecular weight of
253.56 g/mol, and you have it at
14.2 oC. If it is under 1250 torr of
pressure, what is the density of
Cannonium?
Dalton’s Law (Partial
Pressure)
• The total pressure of a mixture of
gases is equal to the sum of all the
partial pressures
• Formula: PT = P1 + P2 + P3 + ...
Dalton
• A 10.0 L flask contains 0.200 moles of
methane, 0.300 moles of hydrogen, and
0.400 moles of nitrogen at 25 C. What is
the partial pressure of each component of
the mixture? What is the total pressure in
atmospheres inside the flask?
Dalton
• The stopcock connecting a 1.0 L bulb
containing oxygen gas at a pressure of 540
torr and a 3.0 L bulb containing helium gas
at a pressure of 776 torr is opened, and the
gases are allowed to mix. Assuming that
the temperature remains constant, what is
the final pressure in the system?
Dalton
• A 450 ml container that contains 2.8 grams
of Oxygen is connected to a 300 ml
container that contains 95 grams of
Hydrogen. They are both at 25C before
and after the valve is opened. What is the
partial pressure of each (in atm), what is
the total pressure (in atm)?
GAS LAW
STOICHIOMETRY
Gas Law Stoichiometry
• After this combustion reaction 12.2 L
of carbon dioxide is left. How many
grams of water were produced if the
reaction took place at 1.3 atm and
600 degrees celsius.
C3H8 + O2  CO2 + H2O
Gas Law Stoichiometry
• How many liters of F2 at 30oC and
2.8 atm of pressure are needed to
react with 8 grams of Hydrogen in
the following reaction?
H2 + F2  HF
Gas Law Stoichiometry
• Aluminum bonds with Oxygen to
make Aluminum Oxide (Al2O3). If
you formed 86.5 grams of Aluminum
Oxide at 68 degrees Celsius and 845
torr, what would the volume of the
Oxygen be?
Al + O2  Al2O3
• Ni(CO)4 can be made by the reaction
of finely divided nickel with gaseous
CO. If you have CO in a 1.50 L flask
at a pressure of 418 mmHg at 25oC,
what is the maximum number of
grams of Ni(CO)4 that can be made?
Ni + CO  Ni(CO)4