Chemical Principles 8th Edition by Steven S. Zumdahl - Test Bank

Chemical Principles 8th Edition by Steven S. Zumdahl - Test Bank   Instant Download - Complete Test Bank With Answers     Sample Questions Are Posted Below   1. A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 735 mm above the pool …

$19.99

Chemical Principles 8th Edition by Steven S. Zumdahl – Test Bank

 

Instant Download – Complete Test Bank With Answers

 

 

Sample Questions Are Posted Below

 

1. A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 735 mm above the pool of mercury. What is the pressure of the atmosphere?

  a. 1.03 atm
  b. 194 atm
  c. 0.697 atm
  d. 0.967 atm
  e. 0.735 atm

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.1
KEYWORDS:   gas | gas pressure | general chemistry | phases

 

2. The volume of a balloon is 3.02 L at 22.7°C.  The balloon is heated to 43.6°C.  Calculate the new volume of the balloon.

  a. 1.57 L
  b. 3.02 L
  c. 2.82 L
  d. 3.23 L
  e. 5.80 L

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.2
KEYWORDS:   Charles’s law | empirical gas laws | gas | general chemistry | phases

 

3. Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas.

Which contains the lowest density?

  a. flask A
  b. flask B
  c. flask C
  d. All are the same.
  e. Two of the flasks contain gases at the same density.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.2
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

4. A cylinder of oxygen gas contains 26.4 g of O2.  Another cylinder, twice the volume of the cylinder containing oxygen (and at the same conditions of pressure and temperature), contains CO2 gas.  Assuming ideal behavior, what is the mass of the carbon dioxide?

  a. 13.2 g
  b. 72.6 g
  c. 36.3 g
  d. 52.8 g
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.2
KEYWORDS:   Boyle’s law | empirical gas laws | gas | general chemistry | phases

 

5. Samples of the gases H2(g) and SO2(g) have equal masses and are at the same temperature and pressure.  Calculate the following:

The ratio of volumes .

  a. 32
  b. 0.18
  c. 180
  d. 5.6
  e. 1.0

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.2
KEYWORDS:   Avogadro’s law | empirical gas laws | gas | general chemistry | phases

 

6. A balloon contains 10.0 g of neon gas.  With the temperature kept constant, 10.0 g of argon gas is added.  What happens?

  a. The volume of the balloon expands by more than 2 times.
  b. The volume of the balloon expands by less than 2 times.
  c. The balloon stays the same size, but the pressure increases.
  d. The balloon doubles in volume.
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.2
KEYWORDS:   Avogadro’s law | empirical gas laws | gas | general chemistry | phases

 

7. The volume of a helium balloon is 1.85 L at 24.0°C and 1.00 atm at sea level.  The balloon is released and floats upward.  At a certain altitude, the balloon has a volume of 2.14 L and the temperature is 15.2°C.  What is the atmospheric pressure at this altitude?

  a. 0.538 atm
  b. 1.36 atm
  c. 0.839 atm
  d. 0.891 atm
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.2
KEYWORDS:   combined gas law | empirical gas laws | gas | general chemistry | phases

 

8. Three 1.00-L flasks at 25°C and 725 torr contain the gases CH4 (flask A), CO2 (flask B), and C2H6 (flask C).

In which flask is there 0.039 mol of gas?

  a. flask A
  b. flask B
  c. flask C
  d. all
  e. none

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

9. Body temperature is about 308 K. On a cold day, what volume of air at 273 K must a person with a lung capacity of 2.00 L breathe in to fill the lungs?

  a. 1.13 L
  b. 2.26 L
  c. 1.77 L
  d. 3.54 L
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   Charles’s law | empirical gas laws | gas | general chemistry | phases

 

10. Consider two samples of helium in separate containers of the same volume.  Sample 1 has an absolute temperature four times that of Sample 2.  Both samples are at the same pressure.

Calculate the ratio n1/n2.

  a. 2:1
  b. 1:1
  c. 1:2
  d. 4:1
  e. 1:4

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

11. A cylinder is fitted with a movable piston.  The pressure inside the cylinder is Pi and the volume is Vi.  What is the new pressure in the system when the piston decreases the volume of the cylinder by half?

  a. 2ViPi
  b. 2Pi
  c. (1/4)Pi
  d. (1/2)Pi
  e. Pi2

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   Boyle’s law | empirical gas laws | gas | general chemistry | phases

 

12. A 8.80-g piece of solid CO2 (dry ice) is allowed to sublime in a balloon. The final volume of the balloon is 1.30 L at 290. K. What is the pressure of the gas?

  a. 7.36 × 10–5 atm
  b. 0.273 atm
  c. 3.66 atm
  d. 1.61 × 102 atm
  e. 44.6 atm

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

13. Given a cylinder of fixed volume filled with 1 mol of argon gas, which of the following is correct? (Assume all gases obey the ideal gas law.)

  a. If a second mole of argon is added to the cylinder, the ratio T/P will remain constant.
  b. If the temperature of the cylinder is changed from 25°C to 50°C, the pressure inside the cylinder will double.
  c. A cylinder of identical volume filled with the same pressure of helium must contain more atoms of gas because He has a smaller atomic radius than argon.
  d. Two of these are correct.
  e. None of these is correct.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

14. Which of the following relationships is not true?

  a. PV = constant when temperature and moles of gas are held constant.
  b. V/T = constant when pressure and moles of gas are held constant.
  c. nT = constant when pressure and volume are held constant.
  d. P/n = constant when volume and temperature are held constant.
  e. All of these are true.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.3
KEYWORDS:   empirical gas laws | gas | general chemistry | phases

 

15. A sample of oxygen gas has a volume of 4.50 L at 27°C and 800.0 torr. How many oxygen molecules does it contain?

  a. 1.16 × 1022
  b. 1.16 × 1023
  c. 2.32 × 1024
  d. 5.8 × 1022
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

16. Mercury vapor contains Hg atoms. What is the volume of 200. g of mercury vapor at a temperature of 822 K and 0.500 atm?

  a. 135 L
  b. 329 L
  c. 82.2 L
  d. 67.2 L
  e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

17. A sample of nitrogen gas has a volume of 180.0 mL at STP.  What volume does the gas occupy if the absolute temperature and pressure are each doubled?

  a. 90.00 mL
  b. 360.0 mL
  c. 720.0 mL
  d. 44.8 L
  e. 180.0 mL

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   empirical gas laws | gas | general chemistry | phases

 

18. Consider a sample of neon gas in a container fitted with a movable piston (assume the piston is massless and frictionless).  The temperature of the gas is increased from 20.0°C to 40.0°C.  The density of neon

  a. decreases less than 10%.
  b. decreases more than 10%.
  c. does not change.
  d. increases more than 10%.
  e. increases less than 10%.

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   empirical gas laws | gas | gas density | general chemistry | phases

 

19. The valve between a 3.00-L tank containing O2(g) at 7.36 atm and a 2.10-L tank containing Ne(g) at 5.08 atm is opened.  Calculate the ratio of partial pressures (O2:Ne) in the container.

  a. 0.592
  b. 1.45
  c. ​1.43
  d. ​2.07
  e. ​0.483

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   Dalton’s law of partial pressures | gas | gas mixtures | general chemistry | phases

 

20. Air is 79% N2 and 21% O2 by volume.  Calculate the density of air at 1.0 atm, 25°C.

  a. 1.18 g/L
  b. 2.46 g/L
  c. 0.590 g/L
  d. 14.1 g/L
  e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

21. Air is 79% N2 and 21% O2 by volume.  Calculate the mass of oxygen in a 2.0-L bottle of air at 1.0 atm, 25°C.

  a. 0.550 g
  b. 2.36 g
  c. 1.81 g
  d. 2.62 g
  e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

22. At STP the mass of 680.0 mL of a certain gas is 0.850 g.  What is a possible identity of this gas?

  a. CO
  b. Ar
  c. O2
  d. CO2
  e. H2

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and
1 atm pressure.

 

23. Which gas sample has the greatest number of molecules?

  a. He
  b. NH3
  c. Cl2
  d. CH4
  e. All the gases have the same number of molecules.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.4
KEYWORDS:   Avogadro’s law | empirical gas laws | gas | general chemistry | phases

 

24. Which gas has the highest density?

  a. NH3
  b. CH4
  c. Cl2
  d. He
  e. All the gases have the same density.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

A plastic bag is weighed and then filled successively with two gases, X and Y. The following data are gathered:

Temperature: 0.0°C
Pressure: 1.00 atm
Mass of empty bag: 20.77 g
Mass of bag filled with gas X: 24.97 g
Mass of 1.12 L of air at conditions given: 1.30 g
Volume of bag: 1.12 L
Molar volume at STP: 22.4 L

 

25. The mass of 1.12 L of gas Y is found to be 6.23 g. The density of gas Y is

  a. 0.180 g/L.
  b. 0.200 g/L.
  c. 10.6 g/L.
  d. 15.6 g/L.
  e. 5.56 g/L.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

26. The molar mass of gas Y is

  a. 89.0 g/mol.
  b. 56.0 g/mol.
  c. 157 g/mol.
  d. 140. g/mol.
  e. 125 g/mol.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

27. It is found that 250. mL of gas at STP has a mass of 1.00 g. What is the molar mass?

  a. 14.0 g/mol
  b. 89.6 g/mol
  c. 22.4 g/mol
  d. 28.0 g/mol
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

28. Air has an average molar mass of 29.0 g/mol. The density of air at 1.00 atm and 30°C is

  a. 40.0 g/mL.
  b. 1.17 g/L.
  c. 1.29 g/L.
  d. 12 g/L.
  e. 29.0 g/L.

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

29. Equimolar amounts of the gases N2 and H2 are mixed in a closed container fitted with a piston (allowing the volume of the container to change, thus keeping the pressure constant).  Calculate the ratio of the final volume of the container to the initial volume of the container when the reaction N2 + 3H2  →  2NH3 goes to completion.

  a. 1
  b. 2/3
  c. 3/2
  d. 1/3
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

30. The density of a certain diatomic gas is 1.696 g/L at STP.  Identify the gas.

  a. Cl2
  b. O2
  c. F2
  d. H2
  e. N2

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

31. Potassium chlorate decomposes upon heating as follows:

2KClO3(s) → 2KCl(s) + 3O2(g)

A 2.72-g sample of KClO3 decomposes, and the oxygen at 23.4°C and 0.935 atm is collected.  What volume of oxygen gas will be collected, assuming 100% yield?

  a. 2.21 mL
  b. 0.577 mL
  c. 0.0456 mL
  d. 0.0684 mL
  e. 0.866 mL

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

32. Calculate the density of nitrogen at STP.

  a. 1.25 g/L
  b. 0.625 g/L
  c. 0.312 g/L
  d. 1.60 g/L
  e. 0.800 g/L

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

33. A volatile liquid produced 0.379 g of vapor in a 262.0-mL flask at 100.0°C and 0.960 atm.  What is the molar mass of the liquid?

  a. 11.9 g/mol
  b. 35.4 g/mol
  c. 46.1 g/mol
  d. 8.22 g/mol
  e. 30.7 g/mol

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

34. What volume of carbon dioxide measured at STP will be formed by the reaction of 1.30 mol of oxygen with 9.00 × 10–1 mol of ethyl alcohol (CH3CH2OH)?

  a. 91.9 L
  b. 8.70 L
  c. 28.0 L
  d. 19.4 L
  e. 40.3 L

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

35. If a 2.15-g sample of a gas occupies 750. mL at STP, what is the molar mass of the gas at 125°C?

  a. 75.0
  b. 3.07 × 10–2
  c. 64.2
  d. 70.1
  e. Not enough information is given.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

36. Into a 3.50-liter container at 25°C are placed 1.10 mol of O2 gas and 4.68 mol of solid C (graphite). If the carbon and oxygen react completely to form CO(g), what will be the final pressure in the container at 25°C?

  a. 0.645 atm
  b. 7.69 atm
  c. 32.7 atm
  d. 40.4 atm
  e. 15.4 atm

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

37. When a mixture is prepared from 15.0 L of ammonia and 15.0 L of chlorine measured at the same conditions, these compounds react according to the following equation:

2NH3(g) + 3Cl2(g) → N2(g) + 6HCl(g)

When the reaction is completed, what are the volumes of the gases (NH3, Cl2, N2, and HCl, respectively)? Assume the final volumes are measured under identical conditions.

  a. 0.00 L, 0.00 L, 5.00 L, and 30.0 L
  b. 0.00 L, 0.00 L, 7.50 L, and 45.0 L
  c. 0.00 L, 5.00 L, 7.50 L, and 45.0 L
  d. 5.00 L, 0.00 L, 5.00 L, and 30.0 L
  e. 0.00 L, 10.0 L, 15.0 L, and 90.0 L

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

38. A mixture of KCl and KClO3 weighing 1.80 g was heated; the dry O2 generated occupied 1.40 × 102 mL at STP. What percent of the original mixture was KClO3? KClO3 decomposes as follows:

2KClO3(s) → 2KCl(s) + 3O2(g)

  a. 37.2%
  b. 72.6%
  c. 42.6%
  d. 63.8%
  e. 28.4%

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

39. An excess of potassium hydroxide is treated with 1.6 L of dry hydrogen bromide gas measured at STP. What is the mass of potassium bromide formed?

  a. 8.2 × 102 g
  b. 8.5 g
  c. 1.0 × 103 g
  d. 1.7 × 103 g
  e. 1.4 × 103 g

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

40. Magnesium metal reacts with hydrochloric acid to form aqueous magnesium chloride and hydrogen gas.  An excess of magnesium is reacted with 20.0 mL of 3.00 M hydrochloric acid, and all of the hydrogen is collected in a balloon at 25°C and 1.00 atm.  What is the expected volume of the balloon?

  a. 0.734 L
  b. 1.47 L
  c. 0.672 L
  d. 22.4 L
  e. 1.34 L

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

41. When 0.72 g of a liquid is vaporized at 110°C and 0.967 atm, the gas occupies a volume of 0.559 L. The empirical formula of the gas is CH2. What is the molecular formula of the gas?

  a. C4H8
  b. CH2
  c. C2H4
  d. C3H6
  e. none of these

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

42. A 3.82-g sample of lead(II) nitrate, Pb(NO3)2, molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 1.70 L. The salt decomposes when heated, according to the equation

2Pb(NO3)2(s) → 2PbO(s) + 4NO2(g) + O2(g)

Assuming complete decomposition, what is the pressure in the cylinder after decomposition and cooling to a temperature of 290. K? Assume the PbO(s) takes up negligible volume.

  a. 0.565 atm
  b. 0.162 atm
  c. 0.784 atm
  d. 0.808 atm
  e. 0.404 atm

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

43. The purity of a sample containing zinc and weighing 0.198 g is determined by measuring the amount of hydrogen formed when the sample reacts with an excess of hydrochloric acid. The determination shows the sample to be 84.0% zinc. What amount of hydrogen (measured at STP) was obtained?

  a. 1.53 × 1021 atoms
  b. 3.42 × 10–3 mol
  c. 0.152 L
  d. 0.0330 g
  e. 1.53 × 1021 molecules

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases | stoichiometry and gas volumes

 

44. At 1000°C and 10. torr, the density of a certain element in the gaseous state is 2.9 × 10–3 g/L. The element is

  a. Ne.
  b. Ar.
  c. He.
  d. Na.
  e. Hg.

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

45. A 1.00-g sample of a gaseous compound of boron and hydrogen occupies 0.820 L at 1.00 atm and 3°C. What is the molecular formula for the compound?

  a. B2H6
  b. B4H10
  c. B5H14
  d. B3H12
  e. BH3

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

46. How many of the following gases at STP are less dense than air at STP?

NH3, He, Kr, and F2

  a. 4
  b. 0
  c. 2
  d. 1
  e. 3

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

47. The oxidation of nitric oxide to nitrogen dioxide is

2NO(g) + O2(g)  →   2NO2(g)

If 100.0 mL of NO (at STP) reacts with 400.0 mL of O2 at STP, calculate the partial pressure of NO2 in the final reaction mixture.

  a. 0.222 atm
  b. 0.286 atm
  c. 0.333 atm
  d. 0.250 atm
  e. 1.00 atm

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
5.5
KEYWORDS:   Dalton’s law of partial pressures | gas | gas mixtures | general chemistry | phases

 

48. A balloon contains an anesthetic mixture of cyclopropane (C3H6) and oxygen (O2) at 160 torr and 550 torr, respectively. What is the ratio of the number of moles of cyclopropane to the number of moles of oxygen?

ncp/no2 = ?

  a. 0.29
  b. ​0.77
  c. ​0.23
  d. ​3.4
  e. ​0.26

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.5
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

49. A 250.0-L cylinder contains 65.0% He(g) and 35.0% Kr(g) by mass at 25.0°C and 1.35 atm total pressure.  What is the partial pressure of He in this container?

  a. 0.675 atm
  b. 0.878 atm
  c. 1.32 atm
  d. 1.35 atm
  e. 0.473 atm

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   Dalton’s law of partial pressures | gas | gas mixtures | general chemistry | phases

 

50. A 0.234-g sample of a gas in a 275-mL container at 23.5°C exerts a pressure of 0.292 atm  What is the molar mass of the gas?

  a. 70.9 g/mol
  b. 0.0141 g/mol
  c. 5.62 g/mol
  d. 32.0 g/mol
  e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

51. A 130.-mL sample of gas is collected over water at 22°C and 753 torr. What is the volume of the dry gas at STP? (The vapor pressure of water at 22°C is 20. torr.)

  a. 111 mL
  b. 135 mL
  c. 130. mL
  d. 119 mL
  e. none of these

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   collecting gases over water | gas | gas mixtures | general chemistry | phases

 

52. A vessel with a volume of 10.1 L contains 3.28 g of nitrogen gas, 0.400 g of hydrogen gas, and 85.0 g of argon gas. At 26.0°C, what is the pressure in the vessel?

  a. 215 atm
  b. 0.516 atm
  c. 8.99 × 104 atm
  d. 5.94 atm
  e. 3.08 atm

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

53. A 275.0-mL sample of O2 is collected over water at 60.0°C.  The total pressure is 755 torr.  What is the volume of the O2 at the STP?  (The vapor pressure of water at 60°C is 149 torr).

  a. 244.0 mL
  b. 224.0 mL
  c. 180.0 mL
  d. 333.0 mL
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   collecting gases over water | gas | gas mixtures | general chemistry | phases

 

54. Oxygen gas, generated by the reaction 2KClO3(s) → 2KCl(s) + 3O2(g), is collected over water at 27°C in a 3.72-L vessel at a total pressure of 730. torr. (The vapor pressure of H2O at 27°C is 26.0 torr.) How many moles of KClO3 were consumed in the reaction?

  a. 0.100 mol
  b. 0.210 mol
  c. 0.0933 mol
  d. 70.9 mol
  e. 1.04 mol

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   collecting gases over water | gas | gas mixtures | general chemistry | phases

 

55. A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO2 has a total pressure of 7.0 atm. What is the partial pressure of CO2?

  a. 2.4 atm
  b. 3.5 atm
  c. 4.9 atm
  d. 1.8 atm
  e. 2.1 atm

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.5
KEYWORDS:   Dalton’s law of partial pressures | gas | gas mixtures | general chemistry | phases

 

56. A 226.4-L cylinder contains 65.5% He(g) and 34.5% Kr(g) by mass at 27.0°C and 1.40 atm total pressure.  What is the mass of He in this container?

  a. 26.5 g
  b. 50.3 g
  c. 76.8 g
  d. 559 g
  e. 33.8 g

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.5
KEYWORDS:   Dalton’s law of partial pressures | gas | gas mixtures | general chemistry | phases

 

57. Three 1.00-L flasks at 25°C and 725 torr contain the gases CH4 (flask A), CO2 (flask B), and C2H6 (flask C).

In which single flask do the molecules have the greatest mass, the greatest average velocity, and the highest kinetic energy?

  a. flask A
  b. flask B
  c. flask C
  d. all
  e. none

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

58. Consider three 1.0-L flasks at STP. Flask A contains N2 gas, flask B contains Kr gas, and flask C contains H2 gas.

In which flask do the gas particles have the lowest average kinetic energy?

  a. flask B
  b. The gas particles in all of the flasks have the same average kinetic energy.
  c. The gas particles in two of the flasks have the same average kinetic energy.
  d. flask C
  e. flask A

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and
1 atm pressure.

 

59. For which gas do the molecules have the highest average velocity?

  a. He
  b. CH4
  c. NH3
  d. Cl2
  e. The molecules of all the gases have the same average velocity.

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

60. For which gas are the collisions elastic?

  a. He
  b. Cl2
  c. CH4
  d. NH3
  e. The collisions are elastic for all the gases.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

61. For which gas do the molecules have the smallest average kinetic energy?

  a. He
  b. CH4
  c. NH3
  d. Cl2
  e. The molecules of all the gases have the same average kinetic energy.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

62. Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas.

In which flask do the molecules have the greatest momentum per impact?

  a. The molecules in all the flasks have the same momentum per impact.
  b. flask C
  c. The molecules in two of the flasks have the same momentum per impact.
  d. flask A
  e. flask B

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

63. Under which of the following conditions does a gas behave most ideally?

  a. STP
  b. P = 2.0 atm, T = –100.0°C
  c. P = 0.50 atm, T = 0.0°C
  d. P = 1.0 atm, T = 100.0°C
  e. P = 0.50 atm, T = 100.0°C

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

64. Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.

Average kinetic energy at T1  :  Average kinetic energy at T2

  a. 2.0
  b. 0.50
  c. 0.71
  d. 1.0
  e. 1.4

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

65. The kinetic-molecular theory of gases does not assume that

  a. gas particles are very small compared to the average distance between the particles.
  b. gas particles collide with the walls of their container in elastic collisions.
  c. the average velocity of gas particles is directly proportional to the absolute temperature.
  d. gases are made up of tiny particles in constant chaotic motion.
  e. All of these are correct.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

66. Which statement about kinetic energy (K.E.) is true?

  a. The K.E. of a body will double if its velocity doubles.
  b. As the velocity of a body increases, its K.E. decreases.
  c. The K.E. of a body is independent of its mass.
  d. All objects moving with the same velocity have the same K.E.
  e. None of these statements is true.

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

67. Consider separate samples of Ar(g) and Ne(g).  For what ratio of absolute temperatures (Ne:Ar) are the average kinetic energies equal?

  a. 1.41
  b. 0.505
  c. 1.98
  d. 1.00
  e. none of these

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

68. Which of the following statements is true concerning ideal gases?

  a. The temperature of the gas sample is directly related to the average velocity of the gas particles.
  b. At STP, 1.0 L of Ar(g) contains about twice the number of atoms as 1.0 L of Ne(g) because the molar mass of Ar is about twice that of Ne.
  c. A gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container.
  d. The gas particles in a sample exert attraction on one another.
  e. All of these statements are false.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

Samples of the gases H2(g) and SO2(g) have equal masses and are at the same temperature and pressure.  Calculate the following:

 

69. The ratio of the root-mean-square velocities .

  a. 180
  b. 32
  c. 0.18
  d. 1.0
  e. 5.6

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

70. The ratio of the forces per wall impact .

  a. 5.6
  b. 0.18
  c. 1.0
  d. 32
  e. 180

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

71. The ratio of average kinetic energies per molecule (H2:SO2)

  a. 0.18
  b. 5.6
  c. 180
  d. 1.0
  e. 32

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

Consider two 1.0-L containers, one containing He(g) at 2.50 atm and 24°C and the other containing Ar(g) at 5.00 atm and 48°C.

 

72. Calculate the ratio of average velocities (He:Ar).

  a. 0.108
  b. 4.98
  c. 0.200
  d. 9.22
  e. none of these

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

73. Calculate the ratio of impacts with the wall per second (He:Ar).

  a. 9.22
  b. 1.64
  c. 4.98
  d. 6.25
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

74. The root-mean-square velocity of N2 gas at 35°C is

  a. 52.0 m/s.
  b. 177 m/s.
  c. 5.58 m/s
  d. 524 m/s.
  e. 16.6 m/s

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   diffusion | gas | general chemistry | molecular speed | phases

 

75. Calculate the temperature at which the average velocity of Ar(g) equals the average velocity of Ne(g) at 25°C.

  a. 25°C
  b. 151°C
  c. 317°C
  d. 49.5°C
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

76. Calculate the ratio of the change in momentum per wall impact for Ar(g) to that for He(g) if the gases are at the same temperature and pressure.

  a. 0.316
  b. 3.16
  c. 9.98
  d. 0.100
  e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

77. The root-mean-square velocity of a gas in a closed container of fixed volume is increased from 345 m/s to 690 m/s.  Which one of the following statements might explain correctly how this change was accomplished?

  a. By pumping in more gas at constant temperature, the pressure was quadrupled.
  b. By heating the gas, the temperature was doubled.
  c. By heating the gas, the pressure was quadrupled.
  d. By pumping out 75% of the gas at constant temperature, the pressure was decreased to 25% of its original value.
  e. None of these statements correctly explains the change.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

78. Calculate the temperature at which the average kinetic energy of O2 gas is twice that of He gas at 10.0°C.

  a. 293°C
  b. 20.0°C
  c. 160.0°C
  d. 2.50°C
  e. 10.0°C

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

79. At 200 K, the molecules or atoms of an unknown gas, X, have an average velocity equal to that of Ar atoms at 400 K. What is X? (Assume ideal behavior.)

  a. CO
  b. F2
  c. He
  d. HF
  e. HBr

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

80. Consider the following gas samples:

  Sample A Sample B
   S2(g) O2(g)
   n = 1 mol n = 2 mol
   T = 800 K T = 400 K
   P = 0.20 atm P = 0.40 atm

Which one of the following statements is false?

  a. Assuming identical intermolecular forces in the two samples, sample A should be more nearly ideal than sample B.
  b. The root-mean-square velocity of molecules in sample A is twice as large as the root-mean-square velocity of molecules in sample B.
  c. The average kinetic energy of the molecules in sample A is twice the average kinetic energy of the molecules in sample B.
  d. The fraction of molecules in sample A having a kinetic energies greater than some high fixed value is larger than the fraction of molecules in sample B having kinetic energies greater than that same high fixed value.
  e. The volume of sample A is twice the volume of sample B.

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
5.8
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

81. Order the following according to increasing rate of effusion:

F2, Cl2, NO, NO2, CH4

  a. CH4     <     NO2     <     NO     <     F2          <     Cl2
  b. Cl2       <     F2           <     NO2     <     CH4     <     NO
  c. Cl2       <     NO2       <     F2         <     NO     <     CH4
  d. CH4     <     NO     <     F2          <     NO2     <     Cl2
  e. F2         <     NO     <     Cl2        <     NO2      <     CH4

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.7
KEYWORDS:   effusion | gas | general chemistry | molecular speed | phases

 

82. Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.

Effusion rate at T1  :  Effusion rate at T2

  a. 1.4
  b. 1.0
  c. 0.71
  d. 0.50
  e. 2.0

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.7
KEYWORDS:   effusion | gas | general chemistry | general concepts | molecular speed

 

83. The diffusion rate of H2 gas is 6.45 times as great as that of a certain noble gas (both gases are at the same temperature).  What is the noble gas?

  a. He
  b. Ar
  c. Kr
  d. Ne
  e. Xe

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.7
KEYWORDS:   effusion | gas | general chemistry | molecular speed | phases

 

84. A sample of N2 gas is contaminated with a gas (gas A) of unknown molar mass. The partial pressure of each gas is known to be 200. torr at 25°C. The gases are allowed to effuse through a pinhole, and it is found that gas A escapes at 2.65 times the rate of N2. The molar mass of gas A is

  a. 3.99 g/mol.
  b. 197 g/mol.
  c. 74.2 g/mol.
  d. 10.6 g/mol.
  e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.7
KEYWORDS:   effusion | gas | general chemistry | molecular speed | phases

 

85. Consider two samples of helium in separate containers of the same volume.  Sample 1 has an absolute temperature four times that of Sample 2.  Both samples are at the same pressure.

Calculate the ratio Z1/Z2.

  a. 4:1
  b. 2:1
  c. 1:2
  d. 1:4
  e. 1:1

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

86. Consider two gas samples:

 

Sample A Sample B

 

Contains SF6(g) Contains SF4(g)
Molar mass = 146 Molar mass = 108
n = 1.00 mol n = 1.00 mol
V = 1.00 L V = 1.00 L
T = 50°C T = ?

 

Calculate the temperature of the SF4(g) sample in which the number of wall impacts per second is the same as in the sample of SF6(g).

  a. –236°C
  b. 437 K
  c. –34°C
  d. 177 K
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

87. Samples of the gases H2(g) and SO2(g) have equal masses and are at the same temperature and pressure.  Calculate the following:

The ratio of rates of impact with the walls (H2:SO2)

  a. 180
  b. 0.18
  c. 5.6
  d. 1.0
  e. 32

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

88. Consider two samples of gas at the same volume and temperature that each contains 1.0 mol of gas.  Sample A contains H2 and sample B contains an unknown gas.  The ratio of the impacts per second of gas A with the walls of the container to the impacts per second of gas B with the walls of the container is 4.  Identify gas B.

  a. Ar
  b. CO2
  c. He
  d. Ne
  e. O2

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.

 

89. Mean free path at T1  :  Mean free path at T2

  a. 0.50
  b. 1.4
  c. 2.0
  d. 0.71
  e. 1.0

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.9
KEYWORDS:   collisions of gas particles | gas | general chemistry | general concepts

 

90. Collision frequency between O2 molecules at T1  :  Collision frequency between O2 molecules at T2

  a. 0.50
  b. 1.0
  c. 1.4
  d. 2.0
  e. 0.71

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.9
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

91. Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas.

In which flask do the molecules have the greatest kinetic energy?

  a. flask A
  b. flask B
  c. flask C
  d. The molecules in all the flasks have the same kinetic energy.
  e. The molecules in two of the flasks have the same kinetic energy.

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

92. Consider three 1.0-L flasks at STP. Flask A contains Ar gas, flask B contains O2 gas, and flask C contains He gas.

In which flask do the gas particles have the highest average velocity?

  a. flask A
  b. flask B
  c. flask C
  d. The gas particles in all the flasks have the same average velocity.
  e. The gas particles in two of the flasks have the same average velocity.

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | kinetic theory of an ideal gas | phases | postulates of kinetic theory

 

93. How is the observed pressure of a gas related to the ideal pressure?

  a. The relationship depends on the gas.
  b. They are equal.
  c. The observed pressure is greater than the ideal pressure.
  d. The observed pressure is less than the ideal pressure.
  e. none of these

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | phases | real gases

 

94. How is the volume of the container related to the volume of an ideal gas?

  a. The volume of the container is less than the volume of an ideal gas.
  b. The relationship depends on the gas.
  c. The volume of the container is more than the volume of an ideal gas.
  d. They are equal.
  e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | phases | real gases

 

95. Which gas, He or H2O vapor, has the lower value of a in the van der Waals equation?

  a. H2O
  b. He
  c. The two gases have the same value of a.
  d. It depends on the conditions of pressure and temperature.

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | phases | real gases

 

96. Which gas, Kr or CO2 , has the lower value of b in the van der Waals equation?

  a. The two gases have the same value of b.
  b. It depends on the conditions of pressure and temperature.
  c. CO2
  d. Kr

 

ANSWER:   d
POINTS:   1
DIFFICULTY:   easy
TOPICS:   5.10
KEYWORDS:   gas | general chemistry | phases | real gases

 

97. The ratio V/n versus the Kelvin temperature of an ideal gas (constant pressure)

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.2
KEYWORDS:   gas | general chemistry | ideal gas law | phases

 

98. The pressure of an ideal gas versus the volume at constant temperature and number of moles

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   gas | general chemistry | ideal gas law | phases

 

99. Volume versus temperature in degrees Celsius for an ideal gas at constant volume and number of moles

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.3
KEYWORDS:   gas | general chemistry | ideal gas law | phases

 

100. The pressure of an ideal gas versus the number of moles at constant temperature and volume

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   b
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.4
KEYWORDS:   gas | general chemistry | ideal gas law | phases

 

101. Force per impact versus the molar mass of the ideal gas

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   collisions of gas particles | gas | general chemistry | general concepts

 

102. The number of wall impacts per second versus the square root of Kelvin temperature for 1 mol of an ideal gas at constant volume

 

Which graph represents the plot?

  a. b. c. d. e. none of these

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.6
KEYWORDS:   gas | general chemistry | ideal gas law | phases

 

103. Consider the decomposition of C5H6O3 as follows:

 

C5H6O3(g) → C2H6(g) + 3CO(g)

 

When a 5.63-g sample of pure C5H6O3 was sealed into an otherwise empty 2.50-L flask and heated to 200°C, the pressure gradually rose to 1.63 atm and remained at that value.  Calculate the fraction of C5H6O3 (by moles) that decomposed.

ANSWER:   37.6%
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

104. A sample of helium gas has been contaminated with argon gas.  At 1 atm and 25°C, the density of the mixture is 0.200 g/L.  What is the volume percent argon in the sample?

ANSWER:   2.77%
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   gas | gas density | general chemistry | ideal gas law | phases

 

105. A certain element (Z) reacts to form three gaseous compounds.  Consider the following data (pressure = 1.0 atm).

 

Compound   Density Temperature Mass % Z
A   1.869 g/L 27°C 69.6%
B   2.316 g/L 127°C 63.2%
C   2.925 g/L 177°C 74.1%

 

Determine the identity of element Z.

ANSWER:   Oxygen
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

106. A gaseous binary compound (which is known to contain nitrogen) has a density 1.94 times that of oxygen gas (at the same temperature and pressure).  When 1.31 g of the compound is completely burned in excess oxygen, 1.21 g of water is formed.  Determine the formula of the compound.

ANSWER:   N4H6
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.4
KEYWORDS:   calculations with the ideal gas law | gas | general chemistry | ideal gas law | phases

 

107. Gas A (MM = 36.0 g/mol) and gas B (MM = 62 g/mol) are present in a mixture that contains 50 molecules A : 326 molecules B.  If these gases effuse through a pinhole into a neighboring evacuated chamber, what will be the ratio of A:B in the chamber?

ANSWER:   0.201
POINTS:   1
DIFFICULTY:   moderate
TOPICS:   5.8
KEYWORDS:   effusion | gas | general chemistry | molecular speed | phases

 

108. A gaseous mixture is 50% helium gas and 50% nitrogen gas by mass.  Determine the percent of the force on the container walls arising from the helium and the ratio of the number of helium impacts to the number of nitrogen impacts on the walls of the vessel.

ANSWER:   87.5% of the force; ratio of impacts = 18.5
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

109. Suppose a sealed flask contains 1.0 L of oxygen gas that is completely converted to ozone (O3) at the same temperature.  Calculate the ratio of the new pressure to the original pressure and the ratio of the number of impacts of ozone molecules with the walls of the container to the number of impacts of oxygen molecules with the walls of the container.

ANSWER:   2/3; 0.544
POINTS:   1
DIFFICULTY:   difficult
TOPICS:   5.8
KEYWORDS:   collisions of gas particles | gas | general chemistry | phases

 

110. Based on the van der Waals equation of state

Which of the following molecules – hydrogen chloride, nitrogen dioxide, or sulfur dioxide – should behave most like an ideal gas.

 

van der Waals constants
     
  a b
  (atm L2 . mol-2) (L . mol-1)
     
HCl 3.667 0.04081
NO2 5.284 0.04424
SO2 6.714 0.05636
     

 

  a. NO2
  b. Must know P and V to answer this question
  c. Must know n to answer this question
  d. SO2
  e. HCl

 

ANSWER:   e
POINTS:   1

 

111. With respect to the Maxwell-Boltzmann probability distribution function of molecular speeds, which of the following is true?

  a. b. A and D
  c. d.
  e.    

 

ANSWER:   e
POINTS:   1

 

112. Which impurity in mined coal, when burned, contributes to the production of acid rain?

  a. Silicon
  b. Aluminum
  c. Iron
  d. Sulfur
  e. All of the above

 

ANSWER:   d
POINTS:   1

 

113. Near sea level, the atmosphere is composed of 78% nitrogen and 20% oxygen.  Other trace gases make up the remaining 2%.  At room temperature,

  a. all the gas molecules move at the same speed.
  b. the nitrogen gas molecules, on average, move faster than the oxygen molecules.
  c. the nitrogen gas molecules, on average, move slower than the oxygen molecules.
  d. some nitrogen gas molecules could move faster than some of the oxygen gas molecules.
  e. some nitrogen gas molecules could move slower than some of the oxygen molecules.
  f. B and D
  g. C and D
  h. B, D, and E

 

ANSWER:   h
POINTS:   1

 

114. ​Consider the ideal pressure equation for gases, where a is the proportionality constant, n is the moles of molecules, and V is the gas volume. Identify the correct statement(s) about the proportionality constant.

 

1. A low value for a reflects weak intermolecular forces among the gas molecules.

2. A high value for a reflects weak intermolecular forces among the gas molecules.

3. Among the gases H2, N2, CH4, and CO2, H2 has the lowest value for a.​

  a. 1 only
  b. 2 and 3
  c. 1 and 3
  d. 2 only
  e. 3 only

 

ANSWER:   c
POINTS:   1
DIFFICULTY:   Easy
KEYWORDS:   5.11
NOTES:   general chemistry

 

115. A scrubber removes the sulfur dioxide from the exhaust gas before it is emitted from a power plant stack. Which of the following compounds is used in the scrubbing process?

  a. Powdered limestone
  b. Solid slaked lime​
  c. Aqueous potash
  d. Powdered gypsum
  e. Solid graphite

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   Easy
TOPICS:   5.12
KEYWORDS:   general chemistry

 

116. Determine the collision frequency for an oxygen molecule (M = 3.20 × 10-2 kg/mol) in a sample of pure oxygen gas at 35°C and 1.7 atm. Assume that the diameter of an O2 molecule is 300 pm.

  a. ​9 × 109 s-1
  b. 2 × 109 s-1
  c. 4 × 109 s-1
  d. ​5 × 109 s-1
  e. ​7 × 109 s-1

 

ANSWER:   e
POINTS:   1
DIFFICULTY:   Difficult
TOPICS:   5.9
KEYWORDS:   general chemistry

 

117. Calculate the mean free path in a sample of oxygen gas (M = 3.20 × 10-2 kg/mol) at 35°C and 1.7 atm. Assume that the diameter of an O2 molecule is 300 pm.

  a. 0.6 × 10-7 m
  b. ​0.2 × 10-7 m
  c. 1.3 × 10-7 m
  d. 2.5 × 10-7 m
  e. 3.3 × 10-7 m

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   Difficult
TOPICS:   5.9
KEYWORDS:   general chemistry

 

118. ​Complete the following conversion:

1 atm = 760 mm Hg = _____ torr = _____ pascals

  a. 760, 105
  b. 700, 124
  c. 820, 13-2
  d. ​940, 192
  e. 650, 12-3

 

ANSWER:   a
POINTS:   1
DIFFICULTY:   Easy
TOPICS:   5.1
KEYWORDS:   general chemistry

 

 

Additional information

Add Review

Your email address will not be published. Required fields are marked *