Hemet High  Honors Chemistry
Name:_______________________ Pd:__
Chapter 11 Homework Packet
Date
Assigned
Date
Due
Assignment
Stamp
All Notes Completed and Attached
____/10 pts
Dalton’s Law Worksheet
Boyle’s Law and
Charles’ Law Worksheet
Gay-Lussac’s Law and
Combined Gas Law Worksheet
Gas Volume, Ideal Gas Law, and
Graham’s Law Worksheet
Chapter 11 Review
Pg 393 #59-65, 68-70
-Due end of class on Wednesday!
Final Packet
___/70
Ch 11 Test will be on
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Hemet High  Honors Chemistry
11  Gases
Notes
Section 1: Gases and Pressure
Units of Pressure
 Millimeters of Mercury (mm Hg) is the most common because mercury barometers are most often used.
Average atmospheric pressure at sea level and at 0°C is ____________________.

________ is another name for pressure when a mercury barometer is used in honor of Torricelli for his
invention of the barometer. _____________ = _______________

One atmosphere of pressure (1 atm) is defined as being exactly equivalent to ________________.

One pascal (Pa) is defined as the pressure exerted by the force of one Newton acting on an area of one
square meter. Can also be expressed in kilopascals (kPa).
1 atm = 1.01325 x 105 Pa = 101.325 kPa = 760 mm Hg = 760 torr
Standard Temperature and Pressure
 Because volumes of gases change so much when the temperature or pressure changes, scientists have agreed
on standard conditions of exactly ___________________________________.

These are called standard temperature and pressure or ________________.

Example:
The average atmospheric pressure in Big Bear, CA is 0.971 atm. Express this pressure in
(a) mm Hg
(b) kPa.
Dalton’s Law of Partial Pressures
 Partial Pressure is the pressure of each gas in a mixture of gases.

Dalton’s Law of Partial Pressure states that the total pressure of a gas mixture is the sum of the partial
pressures of the component gases.
PT = P1 + P2 + P3 + …

PT is the total pressure and P1, P2, P3, and so on, are the partial pressures of the component gases.

Examples:
A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressure of the 3 gases
are 2.00 atm, 3.00 atm, and 4.00 atm, respectively. What is the total pressure inside the container?
A container with two gases, helium and argon, has a total pressure of 4.00 atm. If the partial pressure
of helium is 2.30 atm, what is the partial pressure of argon?
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Gases Collected by Water Displacement

Gases produced in the laboratory are often collected over water, through a method known as water
displacement. Water molecules mix with the gas molecules and the resulting water vapor exerts its own
pressure, known as vapor pressure.

The pressure of the water vapor must be taken into account when determining the pressure of the gas.
Patm = Pgas + PH20


The vapor pressure of water is dependent on temperature (Table A-8 on page 859).
Examples:
Oxygen gas from the decomposition of potassium chlorate, KClO3, was collected by water
displacement. The barometric pressure and the temperature during the experiment were 731.0 torr
and 20.0°C. What was the partial pressure of the oxygen collected?
Some Hydrogen gas is collected over water at 20.0°C. The partial pressure of hydrogen is 742.5 torr.
What was the barometric pressure at the time the gas was collected?
Section 2: The Gas Laws
Boyle’s Law: Pressure-Volume Relationship
P1 x V1 = P2 x V2

What must stay constant for Boyle’s Law to work? ___________________________________


Pressure can be in any unit, but both must be the same.
Volume can be in any unit, but both must be the same.

Example:
A sample of oxygen gas has a volume of 150.0 mL when its pressure is 0.947 atm. What will the
volume of the gas be at a pressure of 0.987 atm if the temperature remains constant?
A balloon filled with helium gas has a volume of 500 mL at a pressure of 1 atm. If the pressure
decreases to 0.5 atm and the temperature remained the same, what volume does the gas now occupy?
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Charles’s Law: Volume-Temperature Relationship
V1 = V2
T1 = T2

What must stay constant for Charles’s Law to work?

Volume can be in any unit, but both must be the same.

Temperature must in ________________. K = 273 + °C

Example:
A sample of Neon gas occupies a volume of 752 mL at 25°C. What volume will the gas occupy at 50°C
if the pressure remains constant?
A sample of Nitrogen gas in a container has a volume of 375 mL at 0.0°C. To what temperature must
the gas be heated to occupy a volume of 500.0 mL?
Gay-Lussac’s Law: Pressure-Temperature Relationship
P1 = P2
T1 = T2

What must stay constant for Gay-Lussac’s Law to work?


Pressure can be in any unit, but both must be the same.
Temperature must in Kelvin. K = 273 + °C

Example:
The gas in a container is at a pressure of 3.00 atm at 25°C. Directions on the container warn the user
not to keep it in a place where the temperature exceeds 52°C. What would the gas pressure in the
container be at 52°C?
A sample of helium gas has a pressure of 1.20 atm at 22°C. At what Celsius temperature will the
helium reach a pressure of 2.00 atm, assuming constant volume?
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The Combined Gas Law
P1 V1 = P2 V2
T1
T2

This law works when nothing is staying constant.


Pressure can be in any unit, but both must be the same.
Volume can be in any unit, but both must be the same.

Temperature must in Kelvin. K = 273 + °C

Example:
A helium-filled balloon has a volume of 50.0 L at 25°C and 1.08 atm. What volume will it have at
0.855 atm and 10°C?
The volume of a gas is 27.5 mL at 22.0°C and 0.974 atm. If the volume decreased to 26.3 ml at 0.993
atm, what is the new temperature of the gas?
Section 3: Gas Volumes and the Ideal Gas Law
Molar Volume of a Gas
 Standard Molar Volume of A Gas: the volume occupied by one mole of a gas at STP is 22.4 L.
22.4 L or 1 mol
1 mol
22.4 L



Using this conversion, you can get from grams  moles  Liters or vice versa.
Remember: this only works at STP
Examples:
(a) What volume does 0.8980 mol of gas occupy at STP?
(b) What quantity of gas, in moles, is contained in 2.21 L at STP?
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The Ideal Gas Law
 The Ideal Gas Law is the mathematical relationship among pressure, volume, temperature, and the number
of moles of gas.
PV = nRT
P = Pressure
V = Volume
R = ideal gas constant
n = number of moles
T = Temperature
Ideal Gas Constant


The value you will use is R = 0.0821 L · atm
mol · K
It may be necessary to convert units sometimes.
Example:
What is the pressure in atmospheres exerted by a 0.750 mol sample of nitrogen gas in a 10.0 L
container at 298 K?
Section 4: Diffusion and Effusion
Graham’s Law of Effusion

: the gradual mixing of 2 or more gases due to their spontaneous, random motion.

: the process whereby the molecules of a gas confined in a container randomly pass
through a tiny opening in the container.
𝑹𝒂𝒕𝒆 𝒐𝒇 𝒆𝒇𝒇𝒖𝒔𝒊𝒐𝒏 𝒐𝒇 𝑨
𝒎𝒐𝒍𝒂𝒓 𝒎𝒂𝒔𝒔 𝒐𝒇 𝑩
=√
𝑹𝒂𝒕𝒆 𝒐𝒇 𝒆𝒇𝒇𝒖𝒔𝒊𝒐𝒏 𝒐𝒇 𝑩
𝒎𝒐𝒍𝒂𝒓 𝒎𝒂𝒔𝒔 𝒐𝒇 𝑨


Gas ____ is the heavier gas and Gas ___ is the lighter gas, based on their molar masses.
Examples:
Compare the rates of effusion of hydrogen and oxygen at the same temperature and pressure.
Compare the rates of effusion of helium and argon at the same temperature and pressure.
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