UNIT SEVEN
GASES
CHEMISTRY
UNIT 7: GASES
Overview
During this unit, students will use the kinetic theory to differentiate between the properties of
real and ideal gases. They will investigate and calculate Charles’ Law, Boyles’ Law, GayLussac’s Law, the Combined Gas Law, the Ideal Gas Law, Dalton’s Law of partial pressures,
Graham’s Law of Difffusion/Effusion, and Avogadro’s Hypothesis.
Problems to be aware of:
 Algebraic manipulation of the gas laws.
Suggested Time Allotment
5 Blocks (2 Weeks)
Conceptual Framework
Kinetic Theory & Gases
Kinetic Theory of Gases
Gas Variables
Gas Laws
Real Gases
Pressure
Ideal Gases
Temperature
Volume
Moles
Number of Particles
Avogadro’s
Hypothesis
Boyle’s Law
Charles’ Law
Gay-Lussac’s Law
Combined Law
Ideal Gas Law
Dalton’s Law of
Partial Pressure
Graham’s Law
Interpret Graphs
Related VA Standards of Learning
SOL CH.4
The student will investigate and understand that quantities in a chemical reaction
are based on molar relationships. Key concepts include
c. partial pressure; and
d. gas laws
SOL CH.5
The student will investigate and understand that the phases of matter are
explained by kinetic theory and forces of attraction between particles. Key
concepts include
a. pressure, temperature, and volume.
Instructional Objectives
7.1
Properties of Gases
7.1.1
Review the behavior of a gas using the kinetic molecular theory.
7.1.2
Identify the four variables that describe a gas.
7.2
Gas Laws
7.2.1
Describe the effect of pressure on the volume of a gas (Boyle’s Law).
7.2.2
Describe the effect of temperature on the volume of a gas (Charles’ Law).
7.2.3
Describe the effect of temperature on the pressure of a gas (Gay-Lussac’s Law).
7.2.4
Use the Combined Gas Law equation to solve problems.
7.2.5
Explain and solve problems using the Ideal Gas Law.
7.2.6
Distinguish between a real gas and an ideal gas.
7.2.7
State Avogadro’s hypothesis.
7.2.8
State Dalton’s law of partial pressures and calculate partial pressures.
7.2.9
State Graham’s law of diffusion/effusion. Relate molar mass to rate of
diffusion/effusion.
7.2.10 Interpret graphs involving the gas laws.
Enduring Understanding
 The behavior of gas particles can be described and predicted using kinetic theory.
Essential Question
 How are gas behaviors predicted from variables and mathematical relationships?
Guiding Questions





What are the assumptions of the Kinetic Molecular Theory as it relates to gases?
How are gases affected by changes in volume, pressure, temperature, and number of moles?
How is the partial pressure of a gas related to the total pressure of a mixture of gases?
How is Avogadro’s Principle used in the derivation of the ideal gas law?
How can we use the rate of effusion of gases to determine molar masses?
What Students Should Know
 The pressure and volume of a sample of a gas at constant temperature are inversely
proportional to each other (Boyle’s Law).
 At constant pressure, the volume of a fixed amount of gas is directly proportional to its
absolute temperature (Charles’ Law).
 The sum of the partial pressures of all the components in a gas mixture is equal to the total
pressure of a gas mixture (Dalton’s Law of partial pressures).
 Ideal Gas Law states that PV = nRT
 Pressure units include kPa, mm of Hg, and atm.
 The Kinetic Molecular Theory is a model for predicting and explaining gas behavior.
 Gases have mass and occupy space.
 Gas particles are in constant, rapid, random motion and exert pressure as they collide.
 Gas molecules with the lightest mass travel fastest.
 Relatively large distances separate gas particles from each other.
 An Ideal Gas does not exist, but this concept is used to model gas behavior.
 A Real Gas has intermolecular forces and particle volume and can change states.
 Equal volumes of gases at the same temperature and pressure contain an equal number of
particles.
What Students Should Be Able To Do

Solve problems and interpret graphs involving the gas laws.
Instructional Resources
Text: Modern Chemistry, Chapter 11 - pp. 360-399.
Chemistry Unit 7 Activities: Volume-Temperature Relationships in Gases, The Collapsing Soft Drink
Can, and Gas Law Olympics.
.
Suggested Assessment Evidence
Pre-Assessment
 Student-led discussion on the relationship between the four variables that describe a gas.
On-going Assessment
 Use frequent questioning strategies ranging from basic to upper level thinking skills.
Suggestions include:
 Using the kinetic molecular theory, describe the behavior of gases.
 How do pressure and/or temperature affect the volume of a gas?
 How does temperature and/or volume affect the pressure of a gas?
 Use the combined gas law equation to solve problems.
 Explain and solve problems using the Ideal Gas Law
 What is the difference between a real gas and an ideal gas?
 What is Avogadro’s hypothesis?
 What is Dalton’s law of partial pressures?
 What corrections must be made to the gas laws when gases are collected over water in
the laboratory?
 Calculate partial pressure.
 What is Graham’s law of diffusion/effusion?
 How does molar mass affect the rate of diffusion/effusion?
 Interpret graphs about the gas laws.
Summative Assessment
 Quizzes, tests, summative projects
Suggested Learning Activities
 Boyle’s Law: Pressure – Volume Relationship in
Gases, Chemistry with Computers Vernier
 Volume -Temperature Relationships in Gases Lab
(Activity Section)
 Collapsing Soft Drink Can (Activity Section)
 QuickLab-Diffusion Modern Chemistry p. 387.
 Chapter Lab-Mass and Density of Air at Different
Pressures, Modern Chemistry pp. 398-399.
 Lab Manual-“Skills Practice Experiments” Boyle’s
7.2 Gas Laws
Law, pp. 41-46 and Molar Volume of Gas, pp. 47-53.
 Gas Law Olympics (Activities Section)
5.3 Stoichiometry
 Stoichiometric Relationships and Limiting Reactants (S’Mores)
(Activities Section)
 The Great Kool-Aid Challenge (Limiting Reactants and Kool-Aid)
(Activities Section)
 QuickLab-Limiting Reactants in a Recipe Modern Chemistry p.
316.
 Get the Lead Out (Activities Section)
 Interesting Websites:
http://science.widener.edu/svb/pset/stoichio.html
(Hints for solving stoichiometry problems)
http://www.chem4kids.com/files/react_stoichio.html
(Stoichiometry tutorial - simple concepts)
http://science.widener.edu/svb/pset/formula.html
(Problem worksheet for stoichiometry)
Unit 7 Gases – Lessons
A-B Day Thur Fri Mar31-Apr 1
Critique Hearting Curve Quiz
ReCap Thermochemistry
Introduction to Gases
Restate Kinetic Molecular Theory
State 3 Assumptions associated with IDEAL
GASES
Describe the Kelvin Temperature Scale
Procedures:
Hook: recap Thermo – link to Gases
1.Critique Heating Curve
2.Complete CA (CPS) Unit 6 SOL
questions.
3.Introduce Gases, Chapter 11, Section
Materials:
MOBI
CPS
Textbook
OnlineTextbook
HW:
2. Discuss Key Terms p
3.Complete Practice Problems p, 367
4. Complete SR p. 367
CHECKLIST of STRATEGIES:
Technology:
Reading:
Writing:
Cooperative Learning:
Differentiation:
Manipulatives:
Multiple Intelligences:
Vocabulary :
Questioning:
A-B Day 43 Fii-Mon Feb 4 & 7
Chemical Reactions
1.List evidences of a chemical reaction
2.List 3 requirements for a correctly written
chemical formula
3.Write a word equation and a formula
equation for a sample chemical reaction
4.Balance a formula equation by inspection
5.List the 5 types of chemical reactions
6.Write and label an example of each of the
5 types of chemical reactions
CHECKLIST of STRATEGIES:
Technology:
Reading:
Writing:
Cooperative Learning:
Differentiation:
Manipulatives:
Multiple Intelligences:
Vocabulary :
Questioning:
Day 44 A-B Tues-Wed Feb 8-9
Chapter 8, Sec 2-3 Types of Chemical
Reactions
1.Identify TYPES OF CHEMICAL
REACTIONS
2.Predict the products of simple reactions
given the reactants
Compass to 2015 Strategies:
Critical Thinking:
Creative/Innovative Thinking:
Problem Solving :
Information Literacy :
Listening :
Collaboration
Communication :
Social Responsibility :
Sustainablility:
Interdependence :
Health Literacy:
Procedures:
Hook: Recap Writing & Balancing Eq
1.Critique SemesterEXAM
2. Discuss Key Terms p. 289
3.Complete Practice Problems p268, 272,
& 274
4. Complete SR p. 272
5.Complete SR p. 284
Closure: Preview Section2
Lesson Critique:
Compass to 2015 Strategies:
Critical Thinking:
Creative/Innovative Thinking:
Problem Solving :
Information Literacy :
Listening :
Collaboration
Communication :
Social Responsibility :
Sustainablility:
Interdependence :
Health Literacy:
Procedures:
1.Complete SR p. 284
2. Quick Lab p. 284
Lesson Critique:
Materials:
MOBI
CPS
Textbook
OnlineTextbook
HW:
2. Discuss Key Terms p. 289
3.Complete Practice Problems p268,
272, & 274
4. Complete SR p. 272
5.Complete SR p. 284
Materials:
Textbook
HW:
Study for Unit 4 EXAM (Chp 6&7)
B-A Day 44 Tues-Wed Jan 26-27
EXAM UNIT 4 (Chp 6&7)
Procedures:
Materials:
1Complete Unit 4 EXAM
Unit 4 EXAM
1 Successfully complete Unit 4 EXAM
END OF SEMESTER I
HW:
Prepare for Semester I Exam
Study Quarter I EXAM
Study Unit 4 EXAM
(Unit 4 EXAM will be returned by end
of day 3PM, 1/26/10)