Name ate lass HPTER 14 HPTER SSESSMENT Gases Reviewing Vocabulary Match the definition in olumn with the term in olumn. olumn 1. Equal volumes of gases at the same temperature and pressure contain equal numbers of particles. 2. One mole of any gas will occupy a volume of 22.4 L at STP. 3. R represents the relationship among pressure, volume, temperature, and number of moles of gas present. 4. Temperature, pressure, and volume are related for a fixed amount of gas. 5. The physical behavior of an ideal gas can be expressed in terms of the pressure, volume, temperature, and number of moles of gas present. olumn a. vogadro s principle b. oyle s law c. harles s law d. combined gas law e. Gay-Lussac s law f. ideal gas constant g. ideal gas law h. molar volume 6. The pressure of a given mass of gas varies directly with the kelvin temperature when the volume remains constant. opyright Glencoe/McGraw-Hill, a division of the McGraw-Hill ompanies, Inc. 7. The volume of a given amount of gas held at a constant temperature varies inversely with the pressure. 8. The volume of a given mass of gas is directly proportional to its kelvin temperature at constant pressure. nswer the following question. 9. Explain why R can have different numerical values. hapter ssessment hemistry: Matter and hange hapter 14 79
Name ate lass HPTER 14 HPTER SSESSMENT Understanding Main Ideas (Part ) Each of the following examples gives a change in volume, temperature, amount, or pressure of a gas sample. Indicate whether the other variable mentioned would increase or decrease as a result. If a variable is not mentioned, assume it is constant. 1. dditional gas is added to a soccer ball. The pressure. 2. n inflated balloon is placed in a refrigerator. The volume. 3. piston in an engine compresses the gas into a smaller volume. The pressure. 4. ry ice (solid carbon dioxide) is sealed in a plastic bag. s the temperature increases, the amount of gas present in the bag. 5. ompressed air in scuba tanks cools off as a diver swims at deeper levels. The pressure in the tanks. 6. The volume of an inflated balloon increases when the amount of gas in the balloon. 7. person sits on an air mattress. The pressure. opyright Glencoe/McGraw-Hill, a division of the McGraw-Hill ompanies, Inc. Solve each of the following problems. Show your work. 8. The volume and amount of gas are constant in a tire. The initial pressure and temperature are 1.82 atm and 293 K. t what temperature will the gas in the tire have a pressure of 2.35 atm? 9. What is the volume of 2.3 mol l 2 at 290 K and 0.89 atm? R 0.0821 L atm mol K 10. n inflated balloon is left outside overnight. Initially, it has a volume of 1.74 L when the temperature is 20.2 and the pressure is 1.02 atm. t what temperature will the balloon have a volume of 1.56 L if the pressure falls to 0.98 atm? hapter ssessment hemistry: Matter and hange hapter 14 81
Name ate lass HPTER 14 HPTER SSESSMENT Thinking ritically Use the following graph to answer the questions. 5.0 Sample Pressure (atm) 4.0 3.0 2.0 1.0 Sample 0 0 100 200 300 400 500 600 700 1. What gas law does this graph illustrate? 2. What is the pressure of Sample if the temperature is 400 K? 3. What is the temperature of Sample if the pressure is 2.5 atm? 4. ompare the pressures of Sample and Sample at 400 K. 5. If the samples contain the same amount of gas, which sample has a greater volume? Explain, using the ideal gas law. 6. If the samples have the same volume, which sample contains a greater amount of gas? Explain, using the ideal gas law. opyright Glencoe/McGraw-Hill, a division of the McGraw-Hill ompanies, Inc. 82 hemistry: Matter and hange hapter 14 hapter ssessment
Name ate lass HPTER 14 STUY GUIE FOR ONTENT MSTERY Gases Section 14.1 The Gas Laws In your textbook, read about the basic concepts of the three gas laws. Use each of the terms below to complete the passage. Each term may be used more than once. pressure temperature volume oyle s law relates (1) and (2) if (3) and amount of gas are held constant. harles s law relates (4) and (5) if (6) and amount of gas are held constant. Gay-Lussac s law relates (7) and (8) if (9) and amount of gas are held constant. In your textbook, read about the effects of changing conditions on a sample of gas. opyright Glencoe/McGraw-Hill, a division of the McGraw-Hill ompanies, Inc. For each question below, write increases, decreases, or stays the same. 10. The room temperature increases from 20 to 24. What happens to the pressure inside a cylinder of oxygen contained in the room? 11. What happens to the pressure of the gas in an inflated expandable balloon if the temperature is increased? 12. n aerosol can of air freshener is sprayed into a room. What happens to the pressure of the gas if its temperature stays constant? 13. The volume of air in human lungs increases before it is exhaled. What happens to the temperature of the air in the lungs to cause this change, assuming pressure stays constant? 14. leftover hamburger patty is sealed in a plastic bag and placed in the refrigerator. What happens to the volume of the air in the bag? 15. What happens to the pressure of a gas in a lightbulb a few minutes after the light is turned on? Study Guide for ontent Mastery hemistry: Matter and hange hapter 14 79
Name ate lass HPTER 14 HLLENGE PROLEMS Simple Mercury arometer In Figure 1, a simple mercury barometer is made by filling a long glass tube with mercury and then inverting the open end of the tube into a bowl of mercury. nswer the following questions about the simple mercury barometer shown here. 1. What occupies the space above the mercury column in the barometer s glass tube? Use with hapter 14, Section 14.1 Glass tube Mercury column owl of mercury t sea level t 500 meters above sea level Figure 1 Figure 2 2. What prevents mercury from flowing out of the glass tube into the bowl of mercury? 3. When the barometer in Figure 1 is moved to a higher elevation, such as an altitude of 5000 meters, the column of mercury changes as shown in Figure 2. Why is the mercury column lower in Figure 2 than in Figure 1? 4. Suppose the barometer in Figure 1 was carried into an open mine 500 meters below sea level. How would the height of the mercury column change? Explain why. 5. Suppose the liquid used to make the barometer was water instead of mercury. How would this substitution affect the barometer? Explain. 6. Suppose a tiny crack formed at the top of the barometer s glass tube. How would this event affect the column of mercury? Explain why. opyright Glencoe/McGraw-Hill, a division of the McGraw-Hill ompanies, Inc. 14 hemistry: Matter and hange hapter 14 hallenge Problems
HPTER 14 Gases Name: ate: 1 harles s Law explains the relationship between the temperature and volume of a gas. Which graph best represents this relationship? This question covers TEKS 7. This question tests the material that was covered in the textbook on page 423. 3 Which of these decreases as a given volume of gas increases? Number of gas particles Temperature Pressure Kinetic energy This question covers TEKS 4 and 7. This question on page 421. 4 You are given a balloon filled with a known volume of helium gas. You place the balloon inside a freezer for an hour. How will the balloon look after being in the freezer? opyright Glencoe/McGraw-Hill, a division of The McGraw-Hill ompanies, Inc. 2 The kinetic-molecular theory of gases explains the behavior of gases at the molecular level. ll of the following are part of this theory EXEPT gas molecules experience completely elastic collisions all gas molecules have the same average kinetic energy at the same temperature gas particles are in constant, random motion gas molecules are incompressible This question covers TEKS 4 and 7. This question on pages 419 420. This question covers TEKS 5 and 7. This question tests the material that was covered in the textbook on pages 423 424. Reviewing hemistry: Mastering the TEKS hemistry: Matter and hange 27
HPTER 14 Gases, continued Name: ate: 5 Physicians can use liquid nitrogen to freeze and destroy warts and other skin growths. Knowing the assumptions of the universal gas law, this should surprise you most because if a gas can liquefy, that would imply that gases experience intermolecular forces all gases are volatile and can t be used indoors gas particles are too small to be condensed if a gas can freeze, that would imply that gases can be kept at cold temperatures This question covers TEKS 7. This question tests the material that was covered in the textbook on page 435. 6 avid has two containers of two different gases at the same temperature and pressure. avid could assume all of following EXEPT when the temperature is increased, the volume of both containers will increase when the pressure is increased, the volume of both containers will decrease both containers contain the same number of gas particles when the pressure is decreased, the temperature of both containers will increase This question covers TEKS 7 and 7. This question on pages 421, 423, 426, 430. 7 Which of the following is a gas gas behavior relationship? Helium gas is heated and its volume increases. Oxygen gas is compressed and its temperature increases. Nitrogen gas is placed in a container and the molecules settle to the bottom. Hydrogen gas is cooled and its pressure increases. This question covers TEKS 7 and 7. This question on pages 419, 421, 423, 426. 8 Which question cannot be answered scientifically? How many particles do two gases at the same temperature and pressure contain? What happens to a gas at standard temperature and pressure? How does a gas react when heated to 100º? What happens to a sample of gas at absolute zero? This question covers TEKS 5 and 7. This question on page 423. 9 ir bags, which act as safety devices in cars, contain solid sodium azide. On impact, the sodium azide releases nitrogen gas, which expands the air bag. The main benefit of using a gas instead of another type of matter is that gas molecules are subject to ionic bonding the separation of gas molecules is much greater than the volume they occupy gases won t explode the bag on very hot days gas molecules don t transfer excess kinetic energy This question covers TEKS 5. This question tests the material that was covered in the textbook on pages 419 420. opyright Glencoe/McGraw-Hill, a division of The McGraw-Hill ompanies, Inc. 28 hemistry: Matter and hange Reviewing hemistry: Mastering the TEKS