Chapter 11 Gas Laws

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Chapter 11Gas Laws

• Pages 361-391

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• 7 Stamps
• 7 warm ups!

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Background Information

• Air is composed of several kinds of colorless
  gases.
• Some gases have color.
• Chlorine (Cl2) yellow green
• Nitrogen Dioxide (NO2) brownish-red
• Any 1 mole of a gas occupies a volume of 22.4 L.

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Kinetic Molecular Theory of Gases

• Ideal Gas A hypothetical gas that perfectly fits
  all assumptions of the kinetic-molecular model.
• Real gas A gas that does not behave according to
  the assumptions of the kinetic-molecular theory.

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Kinetic Molecular Theory of Gases

• 1. Gas Consists of large numbers of tiny
  particles that are far apart relative to their
  size.
•  
• 2. Collisions between gases are always elastic.
• An elastic collision is one where there is no net
  loss of total kinetic energy.
• 3. Gas particles are in continuous, rapid, random
  motion.
• 4. There are no forces of attraction between gas
  particles.
• 5. The temperature of a gas depends on the
  average kinetic energy of the particles.

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Gases and Pressure

• Pressure Force per unit area on a surface
• Equation FORCE
• AREA
• ?Pressure area ?
• ?Pressure area ?

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Gases and Pressure
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Gases and Pressure

• Different units for measuring pressure
• (need to memorize!)
• 1 atm
• 760 mmHg
• 101.3 kPa
• 101300 Pa
• 760 torr
• 14.7 lb/in2

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Converting pressure

• 745mmHg_________________Kpa
• 16.5atm __________________lb/in2
• 11.3 lb/in2_________________Kpa
• 100.7Kpa__________________atm

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• Barometer Instrument used to measure pressure.

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Temperature Conversions

• Temperature Kelvin system
• KC273
• -16C__________K
• 8.7C___________K
• 212K__________C
• 0K_____________C

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• Standard Temperature and Pressure (STP)
• Temperature 273 K
• Pressure 1 atm
• 760 mmHg
• 101.3 kPa
• 101300 Pa
• 760 torr
• 14.7 lb/in2

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Daltons Law of Partial Pressure

• The sum of the partial pressures of all the
  components in a gas mixture is equal to the total
  pressure of a gas mixture.
• Equation P1 P2 P3 . PTotal

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Daltons Law of Partial PressureExamples

• A person using an oxygen mask is breathing air
  with 33 oxygen. What is the partial pressure of
  oxygen with the air pressure in the mask is
  110Kpa?

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Daltons Law of Partial PressureExamples

• What is the atmospheric pressure if the partial
  pressure of nitrogen, oxygen and argon are
  604.5mmHg, 162.8mHg, and 0.5mmHg, respectively?

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Daltons Law of Partial PressureExamples

• Oxygen gas from the decomposition of potassium
  chlorate was collected by water displacement. The
  barometric pressure and the temperature during
  the experiment were 731.0 torr and 20.0C. What
  was the partial pressure of the oxygen collected?
  (Hint Use Table A-8 in your text!)

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Pressure and Volume Boyles Law

• The volume of a gas is indirectly proportional to
  the Pressure (_at_ S.T)
• Equation P1V1 P2V2
• Visually

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Pressure and Volume Boyles LawExamples

• A gas has an initial volume of 242cm3 at a
  pressure of 87.6Kpa, what is the volume if the
  pressure changes to standard pressure?

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Pressure and Volume Boyles LawExamples

• A gas at a pressure of 608mmHg is held in a
  container with a volume of 545cm3. The volume of
  the container is then increased to 1065cm3
  without a change in temperature. Calculate the
  new pressure of the gas

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Volume and Temperature Charles Law

• The volume of a gas is directly proportional to
  the temperature (_at_ S.P).
• Equation V1 V2
• T1 T2
• Visually

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Volume and Temperature Charles Law
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• Animations
• http//www.marymount.k12.ny.us/marynet/06stwbwrk/0
  6gas/1esepcharles/esepcharles.html
• http//www.marymount.k12.ny.us/marynet/06stwbwrk/0
  6gas/2slyscharles/2slysflash.html

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Volume and Temperature Charles Law - Examples

• If 20.0L of Oxygen gas are cooled from 100C to
  0C. what is the new volume?

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Volume and Temperature Charles Law - Examples

• A gas can be used as a thermometer. IF it is
  known that the sample of gas has a volume of
  1.00L at 255K, what is the temperature if the
  volume of the same gas sample is changed to 0.45L

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Pressure and Temperature Gay-Lussacs Law

• The pressure of a gas is directly proportional to
  the temperature (_at_ constant volume).
• Equation

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Pressure and Temperature Gay-Lussacs Law -
Examples

• The gas in a container is at a pressure of 3.00
  atm at 25ºC. Directions on the container warn the
  used not to keep it in a place where the
  temperature exceeds 52ºC. What would the gas
  pressure in the container be at a 52ºC?

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Pressure and Temperature Gay-Lussacs Law -
Examples

• At 120.0ºC the pressure of a sample of nitrogen
  is 1.07 atm. What will the pressure be at 205ºC,
  assuming constant volume?

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Combined gas Law

• Incorporates both Boyles and Charles laws. It
  relates pressure, volume and temperature.
• Equation P1V1 P2V2
• T1 T2

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Combined gas LawExamples

• A gas has a volume of 10.0cm3 measured at 75.6Kpa
  and 60.0C, what is the new volume if conditions
  change to STP?

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Combined gas LawExamples

• A gas that had a volume of 955cm3 measured at 58C
  and 108.0Kpa, what will be the new volume if the
  conditions change to 76.0C and 123.0Kpa?

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Gay-Lussacs law of combining volumes of gases

• at constant _______________ and
  _________________, the _______________ of gaseous
  reactants and producs can be expressed as
  _____________ of _________________ _____________
  ________________.
• Animation
• http//www.marymount.k12.ny.us/marynet/06stwbwrk/0
  6gas/1amcslussac/amcsgaylussac.html

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Volume and Moles Avagadros Law

• The volume of a gas is _____________proportional
  to the number of moles of that gas (_at_ S.T).
• Equation
• An anmimation http//www.marymount.k12.ny.us/mary
  net/06stwbwrk/06gas/2lpimavogdro/2lpimavogadro.htm
  l

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Volume and Moles Avagadros LawExamples

• Suppose we have a 12.2 L sample containing 0.50
  moles of oxygen gas at a pressure of 1 atm and a
  temperature of 25 C. If all of this oxygen is
  converted to ozone, O3, at the same temperature
  and pressure, what will be the volume of ozone
  formed?

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Volume and Moles Avagadros LawExamples

• Consider two samples of nitrogen gas. Sample one
  contains 1.5 moles of nitrogen and has a volume
  of 36.7 L at 25 C and 1 atm. Sample 2 has a
  volume of 16.5 L at 25 C and 1 atm. Calculate the
  number of moles of nitrogen in sample 2.

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Gas Stoichiometry

• Standard molar volume of a gas The volume
  occupied by ____________ ___________ of a gas
  at STP has been found to equal ___________________
  ___.
• Example What volume does 0.0685 mol of gas
  occupy at STP?

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Gas StoichiometryExample

• Propane, C3H8, is a gas that is sometimes used as
  a fuel for cooking and heating. It undergoes a
  combustion reaction. What will be the volume of
  oxygen required for the complete combustion of
  0.350L of propane?

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The Ideal Gas Law

• PVnRT
• Where
• P
• V
• n
• R
• T

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The Ideal Gas LawExamples

• What pressure will be exerted by .622 mol of a
  gas contained in 9.22L at 16C. Find pressure in
  Kpa.

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The Ideal Gas LawExamples

• How many moles of a gas will occupy a 486cm3
  flask at 10.C and 66.7 Kpa?

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The Ideal Gas LawExamples

• What volume will be occupied by .684mol of gas at
  99.4Kpa and 9C?

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Diffusion and Effusion

• Diffusion
•  
• Effusion
• Animation
• http//www.marymount.k12.ny.us/marynet/06stwbwrk/0
  6gas/2hdkrdiffusion/2hdkrdiffusion.html

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Diffusion and Effusion

• Grahams Law Rates of _________________ of gases
  at the same _____________ and ______________ are
  inversely proportional to the _______________
  ____________ of their ________________
  ________________.

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Diffusion and EffusionExamples

• Compare the rates of effusion of hydrogen and
  oxygen at the same temperature and pressure.

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Diffusion and EffusionExamples

• Compare the rate of effusion of carbon dioxide
  with that of hydrogen chloride at the same
  temperature and pressure.

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• Animation Summary
• http//www.mhhe.com/physsci/chemistry/essentialche
  mistry/flash/gasesv6.swf
• Web Quest
• http//www.chemheritage.org/EducationalServices/we
  bquest/blimp.htm