Ch 11 Gases STUDY GUIDE Accelerated Chemistry SCANTRON Name /74 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements about pressure is FALSE? 1) A) Pressure is caused by gas molecules colliding with surfaces. B) After creating a pressure difference, the atmospheric pressure can push liquid up a straw. C) The atmosphere has a pressure as the components of air collide with surfaces. D) A deep well dug in the ground must have the pump located at the bottom of well in order to have the water come to the surface. E) All of the above statements are true. 2) Which of the following is NOT part of the Kinetic Molecular Theory? 2) A) The size of the actual gas particles is small compared to the volume of the whole gas. B) There is a large distance between gas particles as compared to their relative size. C) The average energy of the particles is dependent on the molecular mass of the particle. D) Gas particles do not repel each other. E) All of the above statements are part of the Kinetic Molecular Theory. 3) Which of following statements are consistent with the Kinetic Molecular Theory? 3) A) Gases are compressible because the volume of atoms is almost entirely open space. B) Gas particles collide with each other and surfaces without losing any energy. C) Gases assume the shape and volume of their container because they are in constant, straight-line motion. D) Gases have a low density because there is so much empty space between the particles. E) All of the above statements are consistent with the Kinetic Molecular Theory. 4) All of the following statements are consistent with the kinetic molecular theory of gases EXCEPT A) The size of the gas molecules is negligible compared to the total volume of the gas. B) The average kinetic energy of the molecules of a gas is proportional to the temperature of the gas in kelvins. C) Strong attractive forces hold the gas molecules together. D) The gas molecules collide with each other and with the surfaces around them. 4) 5) 1 atm is equal to: 5) A) 760 torr. B) 101,325 Pa. C) 14.7 psi. D) 760 mm Hg. E) all of the above 6) 1 torr is equal to: 6) A) 760 mm Hg. B) 14.7 psi. C) 1 mm Hg. D) 1 Pa. E) all of the above 1
7) A barometer uses mercury because: 7) A) the density of mercury is very large which allows the barometer to be short. B) it is the only liquid metal at room temperature. C) it is a convenient, safe, lightweight material. D) it is the traditional substance used, water could be as easily used. E) All of the above are true. 8) What is the equivalent pressure of 0.905 atm in units of mm Hg? 8) A) 13.3 B) 688 C) 840 D) 0.905 9) What is the equivalent pressure of 1520 torr in units of atm? 9) A) 2.00 B) 203,000 C) 380. D) 1520 10) What is the equivalent pressure of 760 torr in units of mm Hg? 10) A) 29.92 B) 760 C) 1 D) 14.7 11) What is the equivalent pressure of 968 mm Hg in units of atm? 11) A) 1.30 atm B) 0.785 atm C) 1.27 atm D) 968 atm 12) Which of the following statements is TRUE for gases? 1. The temperature of a gas is inversely proportional to its pressure. 2. The volume of a gas is directly proportional to the pressure in torr. 3. The pressure of a gas is due to collisions of the gas molecules. A) 3 only B) 2 only C) 1 only D) 1 and 2 only E) 1 and 3 only 12) 2
13) Boyle's Law is expressed as: 13) A) V is proportional to 1 T B) V is proportional to T C) P is proportional to V D) V is proportional to 1 P 14) To solve problems using Boyle's Law, which mathematical equation should be used? 14) A) P2V1 = P1V2 B) V 1 P1 = V 2 P2 C) P 1 V1 = P 2 V2 D) P1V1 = P2V2 15) One liter of a gas is in a sealed chamber containing a moveable piston. If the piston is moved so that the volume of the gas is compressed to a volume of one-half liter, what will happen to the pressure on the gas? (Assume the temperature is constant and no gas particles are lost.) A) It would be impossible to move the piston since gases are not compressible. B) The pressure will be twice the original value. C) The pressure will be half of the original value. D) The pressure will remain the same. 15) 16) A balloon filled with 0.500 L of air at sea level is submerged in the water to a depth that produces a pressure of 3.25 atm. What is the volume of the balloon at this depth? A) 0.154 L B) 1.63 L C) 6.50 L D) 0.615 L 16) 17) Divers often inflate heavy duty balloons attached to salvage items on the sea floor. If a balloon is filled to a volume of 3.00 L at a pressure of 2.50 atm, what is the volume of the balloon when it reaches the surface? A) 5.50 L B) 1.20 L C) 7.50 L D) 0.833 L 17) 3
18) The initial volume of a gas cylinder is 750.0 ml. If the pressure of a gas inside the cylinder changes from 840.0 mm Hg to 360.0 mm Hg, what is the final volume the gas occupies? A) 3.151 L B) 1.750 L C) 630.0 ml D) 321.4 ml 18) 19) Charles's Law is expressed as: 19) A) V is proportional to 1 P B) V is proportional to T C) P is proportional to V D) V is proportional to 1 T 20) To solve problems using Charles's Law, which mathematical equation should be used? 20) A) P 1 V 2 = P 2 V 1 B) P 2 V 1 = P 1 V 2 C) V 1 T 1 = V 2 T 2 D) T 1 V 1 = T 2 V 2 21) Which one of the following is impossible for an ideal gas? 21) 1 A) = T 1 ( 1 V2 T 2 V1 ) B) V 2 = ( T 2 T 1 ) V 1 C) V 1 T 1 = V 2 T 2 D) V 1 T 1 = V 2 T 2 22) A gas sample occupies 3.50 liters of volume at 20. C. What volume will this gas occupy at 100. C (reported to three significant figures)? A) 2.75 L B) 0.224 L C) 4.46 L D) 17.5 L 22) 4
23) What is the final volume of a balloon that was initially 500.0 ml at 25 C and was then heated to 50 C? A) 542 ml B) 461 ml C) 193 ml D) 1.00 L 23) 24) If the volume of a gas container at 32.0 C changes from 1.55 L to 755 ml, what will the final temperature be? A) -124 C B) 353 C C) 149 C D) 273 C 24) 25) What is the initial temperature of a gas if the volume changed from 1.00 L to 1.10 L and the final temperature was determined to be 255.0 C? A) 207 C B) 480 C C) -41 C D) 232 C 25) 26) A balloon originally had a volume of 0.439 L at 44 C and a pressure of 729 torr. To what temperature must the balloon be cooled to reduce its volume to 378 ml if the pressure remained constant? A) 38 C B) 273 C C) 0 C D) 95 C 26) 27) Gas density can be calculated by dividing the mass of gas by its volume. If you took a balloon of gas and then warmed the balloon in a sunny window, what can now be said about the density of the gas in the balloon? A) The gas density will remain the same. B) The gas density will decrease. C) The gas density will increase. D) The density of gases is independent of temperature. 27) 5
28) What is the proper form of the combined gas law? 28) A) P 1 V 1 T 1 = P 2 V 2 T 2 B) P 1 V 1 T 1 = P 2 V 2 T 2 C) P 1 T 1 V 1 = P 2 T 2 V 2 D) V 1 T 1 P 1 = V 2 T 2 P 2 29) A certain volume of gas was confined in a rigid container. If the pressure of the gas sample in the container was doubled, what happened to the temperature? A) The temperature decreased one-third. B) The temperature doubled. C) The temperature increased four times. D) The temperature became one half. E) not enough information 29) 30) Suppose a balloon was released from the ground and rose to such a height that both the atmospheric pressure and atmospheric temperature decreased. Which statement is TRUE? A) The pressure change acts to decrease the balloon's volume. B) Both the temperature and pressure changes act to increase the balloon's volume. C) Both the temperature and pressure changes act to decrease the balloon's volume. D) The temperature change acts to increase the balloon's volume. 30) 31) If the initial pressure of a system was 1.00 atm and the volume was halved and the temperature was tripled, what is the final pressure? A) 6.00 atm B) 1.50 atm C) 0.667 atm D) 2.00 atm E) not enough information 31) 32) A 325 ml sample of gas is initially at a pressure of 721 torr and a temperature of 32 C. If this gas is compressed to a volume of 286 ml and the pressure increases to 901 torr, what will be the new temperature of the gas (reported to three significant figures in C)? A) 215 C B) 35.2 C C) 335 C D) 62.4 C 32) 6
33) A sample of helium gas initially at 37.0 C, 785 torr and 2.00 L was heated to 58.0 C while the volume expanded to 3.24 L. What is the final pressure in atm? A) 0.681 B) 1.79 C) 3.21 D) 517 33) 34) What is the final volume of a 500.0 ml gas container that increased in temperature from 299 K to 333 K while the pressure increased from 1.00 atm to 1.54 atm? A) 0.362 L B) 0.691 L C) 1.45 L D) 2.77 L 34) 35) What is the initial temperature ( C) of a system that has the pressure decreased by 10 times while the volume increased by 5 times with a final temperature of 150 K? A) 27 B) -198 C) 300 D) 75 35) 36) Avogadro's Law is expressed as: 36) A) n is proportional to 1 T B) V is proportional to n C) P is proportional to n D) V is proportional to 1 n 37) To solve problems using Avogadro's Law, which mathematical equation should be used? 37) A) P 1 V 1 = P 2 V 2 B) n 1 V 1 = n 2 V 2 C) n 1 P 1 = n 2 P 2 D) V 1 n 1 = V 2 n 2 7
38) What happens to the volume of a gas when you double the number of moles of gas while keeping the temperature and pressure constant? A) The volume doubles. B) The volume increases, but more information is needed. C) The volume decreases, but more information is needed. D) The volume is halved. 38) 39) How many moles of gas were added to a balloon that started with 2.3 moles of gas and a volume of 1.4 L given that the final volume was 7.2 L? A) 9.5 B) 12 C) 4.4 D) 0.085 39) 40) If each of the following gas samples have the same temperature and pressure, which sample has the greatest volume? A) 1 gram of H2 B) 1 gram of Ar C) all have the same volume D) 1 gram of O2 E) not enough information 40) 41) For an ideal gas, which of the following pairs of variables are inversely proportional to each other (if all other factors remain constant)? A) n, P B) P, V C) V, T D) P, T 41) 42) The ideal gas law is: 42) A) V = nrt P B) T = PV nr C) P = nrt V D) PV = nrt E) All of the above are forms of the ideal gas law. 8
43) A sample of 0.255 mole of gas has a volume of 748 ml at 28 C. Calculate the pressure of this gas. (R= 0.0821 L atm / mol K) A) 0.784 atm B) 7.84 10-4 atm C) 0.00842 atm D) 8.42 atm 43) 44) What is the pressure of a 3.00 L gas vessel that has 18.0 grams of helium at 25 C? (R= 0.0821 L atm/ mol K) A) 36.7 atm B) 1.81 atm C) 147 atm D) 32.6 atm 44) 45) What is the temperature ( C) of 2.48 moles of gas stored in a 30.0 L container at 1559 mm Hg? (R= 0.0821 L atm/ mol K) A) 302 B) 189 C) -84 D) 29 45) 46) Which conditions can cause nonideal gas behavior by 1) decreasing the space between gas particles or 2) by slowing gas particles so that interactions are significant? A) 1) low pressure ; 2) low temperature B) 1) high pressure; 2) low temperature C) 1) high pressure; 2) high temperature D) 1) low pressure; 2) high temperature 46) 47) A 3.76 g sample of a noble gas is stored in a 2.00 L vessel at 874 torr and 25 C. What is the noble gas? (R= 0.0821 L atm/ mol K) A) He B) Ne C) Ar D) Kr E) not enough information 47) 48) Which of the following diatomic elements would have a mass of 19.08 grams stored in a 3.82 L container at 3,632 mm Hg and 100 C? A) Br2 B) F2 C) O2 D) H2 E) not enough information. 48) 9
49) What is the major component of the air we breathe? 49) A) oxygen B) argon C) nitrogen D) smog E) carbon dioxide 50) What is the third most abundant component of dry air? 50) A) oxygen B) smog C) nitrogen D) carbon dioxide E) argon 51) If a mixture of gases contained 78% nitrogen at a pressure of 984 torr and 22% carbon dioxide at 345 torr, what is the total pressure of the system? A) 1,329 atm B) 17.5 cm Hg C) 1.75 atm D) 639 torr 51) 52) A gas cylinder contains only the gases radon, nitrogen, and helium. The radon has a pressure of 222 torr while the nitrogen has a pressure of 446 torr. If the total pressure inside the cylinder is 771 torr, what is the pressure that is due to the helium? A) 549 torr B) 103 torr C) 668 torr D) 771 torr 52) 53) A "shielding gas" mixture of argon and carbon dioxide is sometimes used in welding to improve the strength of the weld. If a gas cylinder of this two-part mixture was at 4.0 atm pressure and this mixture was 90.% argon, what would be the pressure due to the carbon dioxide gas component? A) 0.40 atm B) 3.6 atm C) 10. atm D) 4.0 atm 53) 54) What problem could happen if deep sea divers used pure oxygen in their tanks? 54) A) oxygen toxicity B) hypoxia C) nitrogen narcosis D) rapture of oxygen 10
55) Human lungs have evolved to breathe oxygen at a pressure as that in the atmosphere, 0.21 atm. If a particular heliox mixture to be carried by a scuba diver is at a pressure of 7.00 atm, what should be the partial pressure due to helium in order to maintain the pressure due to oxygen at 0.21 atm? A) 7.00 atm B) 0.21 atm C) 6.79 atm D) 7.21 atm 55) 56) The vapor pressure of water at 20.0 C is 17.5 mm Hg. If the pressure of a gas collected over water was measured to be 453.0 mm Hg. What is the pressure of the pure gas? A) 0.573 atm B) 0.0230 atm C) 0.619 atm D) 0.596 atm 56) 57) Hydrogen gas produced in the laboratory by the reaction of zinc and hydrochloric acid was collected over water at 25 C. The barometric pressure at the time was 742.5 mm Hg. What is the pressure of dry hydrogen gas if the vapor pressure of water at 25 C is 23.8 mm Hg? A) 718.7 mm Hg B) 766.3 mm Hg C) 742.5 mm Hg D) 760.0 mm Hg 57) 58) Which set of conditions reflect STP? 58) A) 25 C, 14.7 psi B) 373 K, 760 torr C) 273 K, 1 Pa D) 298 K, 1 atm E) 273 K, 760 mm Hg 59) At STP, 12.69 g of a noble gas occupies 14.09 L. What is the identity of the noble gas? (R= 0.0821 L atm/ mol K) A) Ar B) Kr C) Ne D) He E) not enough information 59) 60) Suppose you had a balloon containing 1 mole of helium at STP and a balloon containing 1 mole of oxygen at STP. Which statement is TRUE? A) The balloons will have the same volume. B) The balloons will have the same mass. C) Both A) and B) are true. D) Neither A) nor B) are true. E) not enough information 60) 11
61) Ammonia gas decomposes according to the equation: 2NH 3 (g) N 2 (g) + 3H 2 (g) If 15.0 L of nitrogen is formed at STP, how many liters of hydrogen will be produced (also measured at STP)? A) 30.0 L B) 45.0 L C) 90.0 L D) 15.0 L E) not enough information 61) 62) Water can be formed according to the equation: 2H 2 (g) + O2 (g) 2H 2 O (g) If 8.0 L of hydrogen is reacted at STP, exactly how many liters of oxygen at STP would be needed to allow complete reaction? A) 4.0 L B) 1.0 L C) 8.0 L D) 2.0 L 62) 63) How many liters of O 2 (g) are needed to react completely with 56.0 L of CH 4 (g) at STP to produce CO 2 (g) and H 2 O (g)? Given: CH 4 (g) + 2O 2 (g) CO 2 (g) + H 2 O (g) A) 84.0 L B) 112. L C) 56.0 L D) 28.0 L 63) 64) What is the pressure of 760 mm Hg when expressed in units of in Hg? 64) A) 29.92 in Hg B) 1 in Hg C) 101,325 in Hg D) 760 in Hg 65) What is the final pressure of a system (atm) that has the volume increased from 0.75 L to 1.1 L with an initial pressure of 1.25 atm? A) 1.2 B) 1.8 C) 0.85 D) 1.1 65) 12
66) What is the final volume (L) of 10.0 L system that has the pressure quartered? 66) A) 2.50 B) 17.1 C) 40.0 D) 0.250 67) What is the final volume of a gas that initially occupies 2.50 L at 298 K and is subsequently heated to 321 K? A) 2.96 L B) 2.32 L C) 2.69 L D) 2.23 L 67) 68) What is the change in temperature of a 2.50 L system when it is compressed to 1.75 L if the initial temperature was 298 K? A) 290 K B) -89 K C) -98 K D) 209 K 68) 69) What is the final volume (L) of a 1.00 L system at 315 K and 1.10 atm if STP conditions are established? A) 1.50 B) 0.953 C) 1.05 D) 0.935 69) 70) What is the final pressure (atm) of a 3.05 L system initially at 724 mm Hg and 298 K, that is compressed to a final volume of 2.51 L at 273 K? A) 806 B) 1.60 C) 860 D) 1.06 70) 71) If the number of moles of a gas initially contained in a 2.10 L vessel is doubled, what is the final volume of the gas in liters? (Assume the pressure and temperature remain constant.) A) 6.30 B) 4.20 C) 8.40 D) 1.05 71) 13
72) What is the molecular weight of a gas if a 15.0 g sample has a pressure of 836 mm Hg at 25.0 C in a 2.00 L flask? (R= 0.0821 L atm/ mol K) A) 1.35 amu B) 167 amu C) 11.1 amu D) 176 amu 72) 73) What is the pressure of a 1.0 L flask containing 0.60 g of He at 25 C? (R= 0.0821 L atm/ mol K) 73) A) 15 atm B) 3.7 atm C) 7.3 atm D) 98 atm 74) What is the volume of 28.0 g of nitrogen gas at STP? 74) A) 11.2 L B) 44.8 L C) 22.4 L D) 33.6 L 14