GHW#11- Louisiana Tech University, Chemistry 100. POGIL (Process Oriented Guided
Inquiry Learning) Exercises on Chapter 5. Gaseous State What and Why?
What is kinetic molecular theory of matter? How does kinetic molecular theory distinguish each phase:
gas, liquid and liquid? What is a phase change and how you determine the whether heat is absorbed or
evolved? How intermolecular forces and temperature does plays role in determining the physical state of
matter. What are the properties of gases? How do the following properties of a gas such as pressure volume
and temperature are related? How does the lack of intermolecular forces affect gaseous properties? What is
standard temperature and pressure (STP)? What are gas laws? Why are useful? Why ideality of gases is essential
for these laws to work? Why ideal behavior of gases is essential for the Ideal Gas Law. How do you calculate
molar masses of gases from the gas density? How do you calculate the quantities of gases in chemical
reactions? What is the conversion factor of liters of gases to moles? What is Dalton’s law of partial pressure?
How do you cal calculate the total pressure of a gaseous mixture? What basic reactions take place in the
atmosphere? How does ozone depletion affect us? What green-house gas effect? Is the carbon dioxide level in
the atmosphere already high and global warming real? What are the major zones in the atmosphere? How
does the chemistry and pollution in the troposphere affect us?
,
Objectives are as follows:
Basic Skills
Students should be able to:
5.1 Breathing: Putting Pressure to Work
 Describe the components of the atmosphere
 Explain the main chemicals found in and the reactions producing industrial pollution and urban pollution
 Global Warming and CO2 levels in the atmosphere
5.2 Pressure: The Result of Molecular Collisions
 State the fundamental concepts of the kinetic-molecular theory and use the explain gas behavior
 Explain the properties of gases
5.3 The Simple Gas Laws: Boyle’s Law, Charles’s Law, and Avogadro’s Law
 Solve problems using the appropriate gas laws
5.4 The Ideal Gas Law
 Solve problems using ideal gas laws
5.5 Applications of the Ideal Gas Law: Molar Volume, Density, and Molar Mass of a Gas
 Apply the ideal gas law to finding gas densities and molar masses
5.6 Mixtures of Gases and Partial Pressures
 Daltons Law of partial pressure and applications.
 Perform calculations using partial pressures of gases in mixtures
5.7 Gases in Chemical Reactions: Stoichiometry Revisited
 Calculate the quantities of gaseous reactants and products involved in chemical reactions
5.8 Kinetic Molecular Theory: A Model for Gases
5.9 Mean Free Path, Diffusion, and Effusion of Gases
 Describe the use of Gram’s Law of effusion
5.10 Real Gases: The Effects of Size and Intermolecular Forces
 Describe the differences between real and ideal gases
5.11 Chemistry of the Atmosphere: Air Pollution and Ozone Depletion
 Explain the main features of stratospheric ozone depletion and the role of CFC in it
Resources
Chemistry: Principles of Chemistry: A Molecular Approach, 2nd Edition-Nivaldo J. Tro - Pearson Prentice
Hall
Prerequisites
Chemistry 100, Classification of matter, atomic structure, periodic table and chemical properties, and kinetic
theory of Matter.
What you already know:
Structure of water: Water is a polar molecule with an angular structure. The + end of the dipole is on
oxygen atom and - end is in the direction of hydrogen atoms.
New Concepts
Intermolecular forces There are three types of intermolecular forces: hydrogen bonding, dipolar-dipolar
and London dispersion in the decreasing order.
-
:
Kinetic Molecular Theory (KMT) of matter
Matter is made up of tiny moving particles with certain kinetic energy creating specific physical states:
gas, liquid and solids. KMT postulates that all real gases can be condensed to liquids and then to solids by
lowering the temperature and increasing the pressure which decrease the average speed of the molecules.
Slowly moving molecules are attracted to each other easily. The physical state of a compound is determined
by the temperature and the kinetic energy as well as the intermolecular forces in the substance.
Gaseous State:
 Consists of particles in continuous, random, rapid motion and under going elastic collisions.
 Volume occupied by the particles is negligibly small having no effect on their properties.
 Intermolecular forces between particles have a no effect on their properties because of the rapid molecular
motion and kinetic energy.
 Gases have no fixed volume or shape, take the volume and shape of the container
Gaseous state compared to liquid and solid state
In the gaseous state the distance between molecules are longer compared to liquids or solid-state.
Since the molecules are so far apart from each other in gases, the intermolecular forces between them are
very weak. In liquids and solids, on the other hand, intermolecular forces are much greater as each
molecule is under the attractive forces of surrounding molecules.
Summary of properties of gases, liquids, solids
:
Gases
Liquids
Solids
Distance between molecules
Greatest
Close
Closest
Intermolecular Forces
Weak
Strong
Very strong
Temperature for the phase
Higher
In between
Lower
Properties of gases
Properties of Gases: V, P, T, n
Volume(V): Gases takes up the volume of the container they occupy and measured in liters (L). Pressure(P):
Gases exert a pressure on the walls of the container because of the collision of molecules with the wall. Units
of Pressure
1 atm =
760 torr 1 (atm) = 1.01325 x 105 Pa
1 pascal (Pa)= 1 N m-2 = 1 kg m-1 s-2
1 bar = 105 Pa
Temperature (T, measured in Kelvin): Gaseous state exists normally at higher temperatures compared to
liquid and solid states.
Amount(n): Since gases have a mass and a volume, they are considered as matter. The amount of a gas is
measured in moles.
Gas Laws: Patterns of observations between various Properties of Gases: V, P, T, n
Vα 1/P ; V = k 1/P
to get rid of k : taking two sets of measurements, V1 = k 1/P1; V2 = k 1/P2, and dividing to remove k,
V1/V2 = k / P1 /k P2
V 1/V2 = P2/P1
P1V1 = P2V2
b) Charles Law (V and T): Volume of a gas is directly proportional to Temperature at constant
pressure.
V αT;
V = kT
To get rid of k from V1 = kT1;V2 = kT2
V1/V2 = k/k T1/T2
V1/T1 = V2/T2
* Temperature is in Kelvin
c) Combined gas Law (V, P and T): Boyles and Charles Laws were combined to an equation: P1V1/T1 =
P2V2/T2
d) Avogadro's Law (V and n):
Volume of a gas is directly proportional to moles of gas at constant T and P. Vα n;
= kn;
n = moles of gas
To get rid of k
V1 = k n1; V2 = k n2
V1/V2 = k/k n1/n2
V1/n1 = V2/n2
V
e) Ideal gas Law(n, V, P and T): Ideal gas law combines all properties of gases into a single equation which
has all the variable of a gas V, P, T and n.
PV α nT
PV = k nT; k = R = Universal gas constant
PV = nRT
Universal gas constant (R)
Value of R depends on the units of the pressure. . If atm is used, then.. R = 0.08206
L - atm/ mole k
If torr is used, then..
R = 62.4 L - torr/ mole k
R = 8.314 J/ mole k
What is standard Temperature and Pressure STP
The properties of gases, volume and density should be given along with their T and P. There is a
standard Temperature and Pressure for gases for this purpose.
Standard Temperature is: 0oC or 273.15 K
Standard Pressure is: 760 torr or 1 atm
Volume to mole conversion factor of gases: At STP molar volume of any gas is equal to 22.4 liters.
Name:________________________ Date submitted:_________Group:_____ _
GHW#11 Chapter 5 Gaseous State
Key Questions (relatively simple to answer using the Focus Information)
1. What is gaseous state? How it is different from liquid and solid state?
2. What are the properties of gases and how they are measured?
3. What is a Torricelli barometer and how it measures atmospheric pressure?
4. One atmosphere of pressure is equal to 760 mmHg. This unit is used in the common barometer and
manometer. Determine height (in mm) of a column of liquid bromine if the pressure is one atmosphere.
The densities of mercury and bromine are 13.546 and 3.119 g/cm3, respectively.
5. What are gas laws?
a) Boyle's Law:
b) Charles Law:
c) Combined gas Law:
d) Avogadro's Law:
e) Ideal gas Law:
.
6. What are the postulates of Kinetic Molecular Theory that has been used to explain behavior of gases
(gas laws)?
7.
The volume of a sample of gas is 750. mL at STP. What volume will the sample occupy at 0.0 C and
950. torr?
8.
A 2.00-L flasks at 25 C and 730 torr contain CH4 (methane) gas, how many moles of gas are in the
flask?
9.
A nitrogen sample has a volume of 5.00 L at 30oC and 750.0 torr. How many nitrogen atoms does
it contain?
10. What volume will 32.0 g of O2 occupy at STP?
11. A 2.00-g piece of solid CO2 (dry ice) is allowed to sublime in a balloon. The final volume of the
balloon is 2.00 L at 303 K. What is the pressure of the gas?
12. Four identical 1.0-L flasks at STP containing following gases: 1) He 2) Cl 2 3) CH 4 4) NH 3
Which gas has the:
a) Highest density?
b) Highest average velocity?
c) Fewest atoms?
d) Diatomic molecules?
13. H2 reacts with O2 according to the following equation
2H2 (g) + O2 (g) ---> 2H2O (g)
What volume of oxygen at STP is needed to react with 3.00 moles of hydrogen?
14. How do you calculate the density of a gas?
15. Calculate the density of methane (C2H6) at STP?