PRETEST - Gas Laws Multiple Choice: 35 minute time limit 

1.          Which of the following gases will have the smallest rate of effusion?a) H   b) He   c) N   d) Ne   e) CO 

2.          A gas mixture contains 2.0 moles of helium and 8.0 moles of carbon dioxide and is held under conditions of standard temperature and pressure. What is the partial pressure of the carbon dioxide?a) 2.0atm   b) 0.2atm   c) 8.0atm   d) 0.8 atm   e) none of these 

3.          The temperature of a fixed mass of gas in a rigid container is decreased from 127.00 degrees Celsius to 27.0 degrees Celsius. The initial pressure was 1000. mmHg. Which is closest to the new pressure, in mmHg, after cooling?a) 250   b) 500   c) 750   d) 900   e) 1330   

4.          A gas is collected over water at a temperature where the vapor pressure of water is known to be 25.0 mmHg. The total pressure recorded in the container is 775.0 mmHg, what is the pressure of the “dry” gas, in mmHg, being collected?a) 825   b) 800   c) 775   d) 750   e) 725   

5.          2.00 moles of a gas are contained in a 2.00 liter vessel at a temperature of 300. degrees Celsius at a pressure of 10.00 atm. The gas is allowed to expand to a new volume of 8.00 liters, but at the same time maintaining the original temperature. What is the new pressure?a) 10.0 atm   b) 7.50 atm   c) 5.00 atm   d) 2.50 atm   e) 1.25 atm      

6.          A gas that is confined in a rigid container is heated. Which of the following statements is true?a)       the kinetic energy of the gas particles will decreaseb)       the pressure will increasec)       the density will decreased)       the number of moles of gas will increasee)       the volume will increase

 7.          A gas is held under conditions of standard temperature and pressure. It is found that 44.0 grams

of the gas occupies a volume of 22.4 L under these conditions. What is the gas?a) CO2   b) Cl2      c) F2   d) N2 e) O2

   

8.          A mixture of gases at a constant temperature includes equal numbers of moles of each of the following. Carbon dioxide, Helium, Neon, Oxygen and Nitrogen. Which gas has the lowest µrms?a) He   b) Ne   c) O2   d) N2   e) they all are the same 

9.          Under what conditions do the assumptions associated with the application of an ideal gas hold true?

a)       low pressure and high temperatureb)       high pressure and large volumec)       large volume and high temperatured)       small volume and high temperaturee)       high pressure and low temperature

 

10.       A gas is heated from 23.000 degrees Celsius to 127.0 degrees Celsius at a constant pressure of 10.00 atm. If the initial volume is V, which equation will best identify the new volume?

a)       (20/123) Vb)       (123/20) Vc)       (296/400) Vd)       (400/296) Ve)       none of these

   

11.       Which assumption is part of the kinetic molecular theory?a)       the particles in a gas have a distinct volume measured in mLb)       the particles in a gas attract one another via intermolecular forcesc)       the particles in a gas collide and emit energy to the surroundingsd)       the speed of the particles in a gas is directly proportional to the Kelvin temperaturee)       the particles in a gas can be compressed

 12.       For a substance that remains a gas under the conditions listed,  deviation from the ideal gas law

would be most pronounced at A)-100 C and 5.0 atmB) -100 C and 1.0 atmC) 0 C and 1.0 atmD) 100 C and 1.0 atmE)  100 C and 5.0 atm 

13.       Look at the picture below, illustrating the volume and pressure of three separate, closed containers, all at the same temperature:  

  2.0L                 2.0L             1.0L  2.0atm              2.0atm         1.0atm 

 After stopcocks of all three containers are opened, which is closest to the pressure inside the system (ignore the small volume of the connective capillary tubing).

a)       1.0atm

b)       1.5atmc)       1.8atmd)       2.0atme)       2.2atm 

14.       A hot-air balloon rises. Which is the best explanation for this observation?a)       the pressure on the walls of the balloon increases with increasing temperatureb)       the difference in temperature between the air inside and outside the balloon produces

convection currentsc)       the cooler air outside the balloon pushes in on the walls of the balloond)       the rate of diffusion of cooler air is less than that of warmer aire)       the density inside the balloon is less than that of the surrounding air

   

15.       A rigid metal tank contains helium gas. Which applies to the gas in the tank when some helium is removed at constant temperature?

a)       the volume of the gas decreasesb)       the pressure of the gas decreasesc)       the average speed of the gas molecules decreasesd)       the total number of gas molecules remains the samee)       the average distance between the gas molecules decreases

 16.       Equal numbers of moles of He(g), Ar(g), and Ne(g) are placed in a glass vessel at room

temperature. If the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?

a)       PHe> PNe > PAr

b)       PAr > PNe > PHe

c)       PNe > PAr > PHe

d)       PAr > PHe > PNe

e)       PNe = PHe = PAr

   

17.       Which gas deviates LEAST from ideal behavior?a) SO2   b) Ne   c) CH4   d) N2   e) H2

  

18.       Approximately what volume do 3.0 moles of Kr gas occupy at STP?a)       22.4 Lb)       44.8 Lc)       67.2 Ld)       89.6 Le)       none of the above  

19 – 21.

Questions 19-21 refer to the following gases at 0˚C and 1 atm.a)       Neb)       Xec)       H2

d)       CO2

e)       NO 

19)    Has an average atomic or molecular speed closest to that of N2 molecules at 0˚C and 1atm.

20)    Has the smallest density21)    Has the slowest rate of effusion through a pinhole

   

22. A flask contains 0.50 mole of SO2(g), 1.50 mole of CH4(g) and 1.0mole of O2(g). The total pressure of the gases in the flask is 1000mmHg. Which is closest to the partial pressure of the O2 (g) in the flask?

 a)       800 mmHgb)       667 mmHgc)       500 mmHgd)       333 mmHge)       160 mmHg

   

23.                                What volume of O2(g) is required to react with excess CS2(l) to produce 10.0L of CO2(g)? (Assume all gases are measured at 0˚C and 1atm.)

 a)       30Lb)       10Lc)       1/3 x 22.4Ld)       2 x 22.4Le)       10 x 22.4L

 24. Butane gas, C4H10, burns in excess oxygen gas. When the equation for this reaction is correctly

balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for O2 is

 a)       7b)       9c)       13d)       17e)       26 

25. An 11.2L container will hold about 8.5g of which of the following gases at 0˚C and 1atm? a) SO2

b) N2

c) CO2

d) C4H8

e) NH3

           

     TallY;Effusion/diffusion: 1, 15, 21Dalton: 2, 4, 22Gay lussac: 3Charles: 5, 10KMT: 6, 11, KTM, temp relates to KE 14PvnRT solving for MM (ez with 22.4): 7Vrms: 8, 19Bulbs of gas mixing w/ Partial pressures/Dalton: 12density of gases, hot air balloon: 13, 20Deviation from ideal gas behavior: 9, 16Volume of gas at STP: 18, 25 (but asked differently)Gas stoich 23  Answers:

1)       e

2)      d

3)      c

4)      d

5)      d

6)      b

7)      a

8)      c

9)      a

10)  d

11)  d

12)  a

13)  c

14)  e

15)  b

16)  b

17)  e

18)  c

19)  e

20)  c

21)  b

22)  d

23)  a

24)  c

25)  e