Unit 10: Physical Characteristics of Gases

Unit 10: Physical Characteristics of Gases

Academic Chemistry

Unit 10: Physical Characteristics of Gases

Essential Questions:

How is the kinetic molecular theory used to explain the differences between solid, liquids, and gases?

How are the gas laws used to relate pressure, volume, temperature, and mole quantities?

Vocabulary: List of terms on page 326 Due:

Kinetic Molecular Theory (303)Pressure (308)Gas Laws (313)

Ideal Gas (303)Newton (309)Boyles Law (314)

Elastic Collision (303)Barometer (310)Absolute Zero (317)

Fluid (305)Atmosphere of Pressure (311)Charles Law (317)

Diffusion (305)Millimeter of Mercury (311)Gay-Lussac’s Law (319)

Effusion (306)Pascal (311)Combined Gas Law (321)

Real Gas (306)Standard Temp and Pressure (312) Avogadro’s Law (334)

Standard Molar Volume of a gas (335)

Textbook Readings and Homework:

10 – 1 The Kinetic-Molecular Theory of Matterpage 303-306Problems # 2, 4

10 – 2 Pressurepage 308-312Problems # 1-4

10 – 3 The Gas Lawspage 313-325Problems # 1-5

11 – 1 Volume – Mass Relationships of Gasespage 333-337Problems # 1-5

11 – 2 The Ideal Gas Lawpage 340-346Problems # 2, 4

EOC’s Page 328 #21, 26, 29, 31, 44, 46

Page 357 #14 a, d , 16 a, 17a, 18b, 19b,

Objectives:

  1. Explain the basic assumptions of the Kinetic Molecular theory
  2. List the characteristic properties of a gas
  3. Describe the four measurable properties of a gas (P, V, T, n)
  4. Convert between the various units (K, C, mL, cc, L cm3, atm, mmHg)
  5. Describe pressure in terms of the kinetic molecular theory
  6. State Boyles Law, describe in terms of Kinetic Molecular theory and apply to solve PV problems
  7. State Charles Law, describe in terms of Kinetic Molecular theory and apply to solve V/T problems
  8. State Gay-Lussac’s Law, describe in terms of Kinetic Molecular theory and apply to solve P/T problems
  9. State the Combined Gas Law and apply to solve PV/T problems
  10. Know that the molar volume of any gas is 1 mole = 22.4L at STP
  11. State the Ideal Gas Law and apply to solve PV=nRT problems

Activities and Labs:

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Demo: Vacuum Pump

Demo: Crushing Can

Demo: Liquid Nitrogen

Article: Gas Laws and Scuba

Lab: Cartesian Diver

Project: Hot Air Balloon

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Lab: Boyle’s Law

Boyle’s Law

  1. State Boyle’s Law ______Constant ______
  1. Explain Boyle’s Law in terms of the kinetic theory.
  1. A sample of oxygen gas has a volume of 150 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 is constant?
  1. A cylinder contains 4.30 dm3 of a gas at a pressure of 105.0 kPa. Keeping the temperature constant, a piston is moved in the cylinder until the volume of the cylinder is 2.8 dm3. What is the pressure at this volume?
  1. If 400 cm3 of oxygen are collected at a pressure of 9.80 kPa what volume will the gas occupy if the pressure is changed to 9.40 kPa?
  1. A gas has a pressure of 1.26 atm and occupies a volume of 7.40 L. If the gas is compressed to a volume of 2.93 L, what will its pressure be?
  1. A balloon filled with helium gas has a volume of 500 mL at a pressure of 1 atm. The balloon is released and reaches an altitude of 6.5 km, where the pressure is 0.5 atm. Assuming that the temperature has remained the same, what volume does the gas occupy at this height?
  1. A helium filled balloon contains 125 mL of gas at a pressure of 0.974 atm. What volume will the gas occupy at standard pressure (1 atm)?
  1. A weather balloon with a volume of 1.375 L is released form Earth’s surface at sea level where the air pressure is 1 atm. What volume will the balloon occupy at an altitude of 20.0 km, where the air pressure is 10.0 kPa?

Charles Law

  1. State Charles Law ______Constant ______
  1. Explain Charles Law in terms of the kinetic theory.
  1. A sample of neon gas occupies a volume of 752 mL at 50o C. What volume will the gas occupy at 25o C if the pressure remains constant?
  1. A helium filled balloon has a volume of 2.75 L at 20o C. The volume of the balloon decreases to 2.46 L after it is placed outside on a cold day. What is the outside temperature?
  1. A gas at 65o C occupies 4.22 L. What Kelvin temperature will require reaching a volume of 3.87 L, assuming the same pressure?
  1. A gas at 0o C has a volume of 2.27 m3. What is the volume if the temperature drops to -9o C?
  1. Determine the volume of 19.0 cm3 of a gas at 72o C if the temperature is changed to 502 K.
  1. A balloon filled with oxygen gas occupies a volume of 5.5 L at 25o C. What volume will the gas occupy at 100o C?
  1. At 0o C, the volume of a gas is 375 mL. To what temperature must the gas be heated to occupy a volume of 500 mL?

Gay-Lussac's Law

  1. State Gay-Lussac's Law ______Constant ______
  1. Explain Gay-Lussac's Law in terms of the kinetic theory.
  1. The gas in an aerosol can is at a pressure of 2.00 atm at 20o C. Directions on the can warn the user not to keep the can in a place where the temperature exceeds 52o C. What would the gas pressure in the can be at 52o C?
  1. At 120o C, the pressure of the sample of nitrogen is 1.07 atm. What will the pressure be at 205o C, assuming constant volume?
  1. A sample of helium gas has a pressure of 1.20 atm at 22o C. At what Kelvin temperature will the helium reach a pressure of 2.00 atm?
  1. A flammable gas at 1 atm pressure is stored in a container rated to withstand a pressure of 2.00 atm is at a temperature of 20o C. The sun shines on the container all day and the temperature of the container rises to 120o C. What will be the pressure in the container at this new temperature? Will the container explode?
  1. Before a trip from New York to Boston, the pressure in an automobile tire is 1.8 atm at 20o C. At the end of the trip, the pressure gauge reads 1.9 atm. What is the new Celsius temperature of the air inside the tire?
  1. A sample of gas in a closed container at a temperature of 100o C and a pressure of 3.0 atm is heated to 300o C. What pressure does the gas exert at the higher temperature?
  1. An empty aerosol spray can at room temperature of 20o C is thrown into an incinerator where the temperature reaches 500o C. If the gas inside the empty container was initially at a pressure of 1.0 atm, what pressure did it reach inside the incinerator?

Avogardro’s Law and Molar Volume

  1. A chemical reaction produces 0.45 mol of oxygen gas, O2 at STP. What volume in liters is occupied by this gas?
  1. At STP, what is the volume of 7.08 mol of nitrogen gas, N2?
  1. A chemical reaction produced 89.0 mL of water vapor, H2O, at STP. What is the mass in grams of the gas produced?
  1. At STP, 3 L of Chlorine, Cl2, is produced during a chemical reaction. What is the mass of this gas?
  1. A sample of hydrogen, H2, occupies 14.1 L at STP. How many moles of gas are present? What is the mass of this gas?
  1. At STP, a sample of neon gas, Ne, occupies 550 mL. How many moles of gas does this represent?
  1. You are planning an experiment that requires 0.058 mol of nitrogen monoxide gas, NO. What volume would you need at STP?
  1. What is the volume of 77.0 g of nitrogen dioxide gas, NO2, at STP?
  1. What is the mass of 1.33 mL of oxygen gas, O2, at STP?
  1. Suppose you need 4.22 g of chlorine gas (Cl2). What volume at STP would you expect to use?
  1. How many moles are contained in 5.60 L of chlorine, Cl2, at STP?
  1. Find the mass of 15.0 mL of SO2.

Combined Gas Law

  1. State Combined Gas Law ______Constant ______
  1. A helium filled balloon has a volume of 50.0 L at 25o C and 1.08 atm. What volume will it have at 0.585 atm and 15o C?
  1. The volume of a gas is 27.5 mL at 22o C and 0.974 atm. What will the volume be at 15.0o C and 0.993 atm?
  1. A 700.0 mL gas sample at 1 atm of pressure and 20o C is compressed to a volume of 200.0 mL and the temperature increased to 30.0o C. What is the new pressure?
  1. The volume of gas at 27.0o C and 0.200 atm is 80 mL. What volume will the same gas sample occupy at 20o C and 1 atm of pressure?
  1. What pressure is required to reduce 60.0 mL of a gas at 2 atm at 25o C to 10.0 mL at a temperature of 30o C?
  1. A gas occupying 75 mL at 1 atm and 0o C is heated to 17o C while the pressure is reduce to 0.97 atm. What is the new volume occupied by the gas?
  1. What pressure is required to reduce 55.0 mL of a gas at a pressure of 3 atm and 10o C to 10.0 mL at a temperature of 25o C?

Ideal Gas Law Problems

Use the ideal gas law to solve the following problems:

1)If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 liters, what is the temperature?

2)If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87 0C, how many moles of gas do I have?

3)If I contain 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400 K, what is the pressure inside the container?

4)If I have 7.7 moles of gas at a pressure of 0.09 atm and at a temperature of 56 0C, what is the volume of the container that the gas is in?

5)If I have 17 moles of gas at a temperature of 67 0C, and a volume of 88.89 liters, what is the pressure of the gas?

6)If I have an unknown quantity of gas at a pressure of 0.5 atm, a volume of 25 liters, and a temperature of 300 K, how many moles of gas do I have?

7)If I have 21 moles of gas held at a pressure of 78 atm and a temperature of 900 K, what is the volume of the gas?

8)If I have 1.9 moles of gas held at a pressure of 5 atm and in a container with a volume of 50 liters, what is the temperature of the gas?

9)If I have 2.4 moles of gas held at a temperature of 97 0C and in a container with a volume of 45 liters, what is the pressure of the gas?

10)If I have an unknown quantity of gas held at a temperature of 1195 K in a container with a volume of 25 liters and a pressure of 560 atm, how many moles of gas do I have? ?

11)If I have 0.275 moles of gas at a temperature of 75 K and a pressure of 1.75 atmospheres, what is the volume of the gas?

12)If I have 72 liters of gas held at a pressure of 3.4 atm and a temperature of 225 K, how many moles of gas do I have?

Review Problems

  1. Explain the kinetic molecular theory include all five points.
  1. Describe pressure in terms of the kinetic molecular theory.
  1. Describe Charles’ law in terms of the kinetic molecular theory
  1. Name and write all the gas law equations (Hint: there are 5)
  1. At 32oC, a gas has a volume of 275 mL. The temperature is then increased to 130oC, and the pressure is held constant. What is the new volume?
  1. The pressure exerted on a 240 mL sample of hydrogen gas at constant temperature is increased form 0.428 atm to 0.724 atm. What will the final volume of the sample be?
  1. A sample of gas at 47oC and 1.03 atm occupies a volume of 2.20 L. What volume would this gas occupy at 107oC and 0.789 atm?
  1. A sample of hydrogen at 47oC exerts a pressure of 0.329 atm. The gas is heater to 77oC at constant volume. What will its new pressure be?

9. If the density of an unknown gas is 3.20 g/L at –18oC and 2.17 atm, what is the molar mass of this gas?

Technical Chemistry - Gas Laws Magic Square

You must show your work in the square.Name………………………………

  1. A sample of neon gas occupies a volume of 2.8 L at 1.8 atm. What would its volume be at 1.2 atm?
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  1. A balloon full of air has a volume of 2.75 L at a temperature of 18oC. What is the balloon's volume at 45 oC?
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  1. If 3.0 L of a gas at 20.0 oC is heated to 30.0 oC what is the new volume of the gas?

  1. A sample of argon has a volume of 0.43 mL at 24 oC. At what temperature in degrees Celsius will it have a volume of 0.57 mL?
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  1. To what pressure would you have to compress 48.0 L of oxygen gas at 99.3 kPa in order to reduce its volume to 16.0 L?
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  1. If a barometer at your home reads 768.2 mm of Hg, what is the atmospheric pressure in kPa?

  1. What is the starting volume of a 24.7L gas sample that exerts a pressure of 0.999 atm. It’s original pressure being 1.011 atm.
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  1. What is the starting temperature of 150mL of gas when cooled to 33OC and a volume of 120mL
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  1. What is the volume occupied by 20.4 liters of CO2 at 1200 Torr when it is at STP?

1. 394 K5. 24.4 L 9. 4.2 L

2. 3.01 L6. 298 kPa10. 382.5 K

3. 32.2 L7. 3.1 L11. 847 mm Hg

4. 121 oC8. 102.4 kPa12. 24 oC

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