Chapter 12 Review The Behavior of Gases

1
Chapter 12 ReviewThe Behavior of Gases

• Charles Page High School
• Dr. Stephen L. Cotton

2
Chapter 12 Review - definitions

• Ideal gas constant (R)
• Boyles law
• Daltons law of partial pressures
• Ideal gas law

3
Chapter 12 Review - definitions

• Combined gas law
• Charless law
• diffusion
• partial pressure

4
Chapter 12 Review

• As the temperature of a fixed volume of gas
  increases, the pressure will
• A breathing mixture used by deep-sea divers
  contains He, O2, and CO2. What is the partial
  pressure of the oxygen at 101.3 kPa total
  pressure if PHe 84.0 kPa and PCO2 0.10 kPa?

(increase)
(17.2 kPa)
5
Chapter 12 Review

• Increasing the volume of a given amount of gas at
  constant temperature causes the pressure to
  decrease because
• When a container is filled with 3.00 mol of H2,
  2.00 mol of O2, and 1.00 mol of N2, the container
  pressure is 465 kPa. The PO2

(the molecules are striking a larger area with
the same force)
(155 kPa)
6
Chapter 12 Review

• A box with a volume of 22.4 L contains 1.0 mol
  nitrogen and 2.0 mol hydrogen at 0 oC. What is
  the partial pressure of N2?
• The volume of a gas is doubled while the
  temperature is held constant. The pressure of
  the gas

(101.3 kPa)
(is reduced by one-half)
7
Chapter 12 Review

• As the temperature of the gas in a balloon
  decreases
• The volume of a gas is increased from 0.5 L to
  4.0 L while the temperature is held constant.
  The pressure of the gas

(the average K.E. of particles decreases)
(decreases by a factor of eight)
8
Chapter 12 Review

• A gas occupies 40.0 mL at -123 oC. What volume
  does it occupy at 27 oC, assuming pressure is
  constant?
• A gas occupies a volume of 0.2 L at 25 kPa. What
  volume will the gas occupy at 2.5 kPa?

(80.0 mL)
(2.0 L)
9
Chapter 12 Review

• Which of these changes would NOT cause an
  increase in the pressure of a gaseous system?
• 1. Another gas added to the container
• 2. Additional amount of the same gas are
  added to the container
• 3. Temperature is increased
• 4. Container is made larger

?
10
Chapter 12 Review

• At a certain temperature and pressure, 0.20 mol
  of CO2 has a volume of 3.1 L. A 3.1 L sample of
  hydrogen at the same temperature and pressure

(contains the same number of molecules)
11
Chapter 12 Review

• A gas has a pressure of 655 kPa at 227 oC. What
  will its pressure be at 27 oC, if the volume does
  not change?

(Use Gay-Lussacs law 393 kPa)
12
Chapter 12 Review

• A 10 gram mass of krypton occupies 15.0 L at a
  pressure of 156 kPa. Find the volume of the
  krypton when the pressure is increased to 215 kPa
  at the same temperature.

(Use Boyles law 10.9 L)
13
Chapter 12 Review

• A gas occupies a volume of 180 mL at 35.0 oC and
  95.9 kPa. What is the volume of the gas at
  conditions of STP?

(Use Combined Gas law 151 mL)
14
Chapter 12 Review

• A gas has a volume of 550 mL at a temperature of
  - 55.0 oC. What volume will the gas occupy at
  30.0 oC, assuming constant pressure?

(Use Charless law 764 mL)
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Chapter 12 Review

• What are some differences between a real gas and
  an ideal?

(An ideal gas follows the gas laws at all
conditions of temperature and pressure. The
behavior of a real gas deviates from the gas laws
at low temperatures and high pressure. Also,
kinetic theory assumes the particles of an ideal
gas have no volume or attraction for each other.
Real gases can be liquefied or solidified by
cooling and/or applying pressure.)
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Chapter 12 Review

• Always true, Sometimes true, or Never true
• Two small bicycle pumps are filled with different
  gases one contains He, the other Ar. Using the
  same pressure, it will take longer to force out
  the He than the Ar.
• An ideal gas will continue to contract in volume
  with increasing pressure and reduced temperature
  until absolute zero is reached.

(NT)
(AT)
17
Chapter 12 Review

• Always true, Sometimes true, or Never true
• In order to obtain a value for the number of
  moles using the ideal gas law, one uses the
  conditions of STP.
• The kinetic energy of a moving body is directly
  proportional to the square of its velocity.

(ST)
(AT)
18
Chapter 12 Review

• The gaseous product of a reaction is collected in
  a 25.0 L container at 27 oC. The pressure in the
  container is 216 kPa and the gas has a mass of
  96.0 grams. What is the formula mass of the gas?

(Use Ideal equation 2 44.3 g/mol)
19
Chapter 12 Review

• The separation of uranium-235 from uranium-238
  has been carried out using gaseous diffusion.
  Calculate the relative rates of diffusion of
  gaseous UF6 containing these isotopes
• formula mass UF6 with U-235 349.0
• formula mass UF6 with U-238 352.0

(Use Grahams law 1.004 U-235 / 1 U-238)