1. Liquid mercury freezes at a temperature of -39 ^oC. The freezing point of mercury on the Kelvin scale is:

• A) 234 K
• B) 39 K
• C) 312 K
• D) 273 K

2. To increase the volume of a fixed amount of gas from 100 cm³ to 200 cm³:

• A) increase the temperature from 25.0 to 50.0 ^oC at constant pressure
• B) increase the pressure from 1.00 to 2.00 atm at constant temperature
• C) reduce the temperature from 400 K to 200 K at constant pressure
• D) reduce the pressure from 608 mm Hg to 0.40 atm at constant temperature

3. A sample of gas weighs 0.250 g and occupies a volume of 112 cm³ at STP. The molecular weight of this gas is:

• A) impossible to calculate from the data given
• B) 50.0 g/mol
• C) 2.23 g/mol
• D) 8.0 g/mol

4. The volume in Liters of H₂ (g) (measured at 22 ^oC and 745 mmHg) required to react with 30.0 L CO(g) (measured at 0 ^oC and 760 mmHg) in the reaction CO(g) + H₂ (g) -> C₃H₈ (g) + H₂O(l) is:

• A) 63.5 L
• B) 74.1 L
• C) 77.2 L
• D) 70.0 L

5. A sample of oxygen gas is collected over water at 23 ^oC at a barometric pressure of 751 mmHg (the vapor pressure of water at 23 ^oC = 21 mmHg). The partial pressure of oxygen gas in the sample collected is:

• A) 0.96 atm
• B) 21 mmHg
• C) 751 mmHg
• D) 1.02 atm

6. A gaseous mixture consists of 50.0% O₂ , 25.0% N₂ , and 25.0% Cl₂, by mass. At standard temperature and pressure, the partial pressure of:

• A) Cl₂ (g) is greater than 0.25 atm
• B) O₂ (g) is equal to 380 torr
• C) Cl₂ (g) is less than 0.25 atm
• D) N₂ (g) is equal to 0.20 atm

7. Of the following values, the most likely to be observed for the actual volume of 1.00 mole of He(g) at 0 ^oC and 1000 atm is:

• A) 17.4 mL
• B) 46 mL
• C) 22.4 mL
• D) 11.2 mL

8. If 0.50 mole H₂ (g) and 1.0 mole He(g) are compared at standard temperature and pressure, the two gases will:

• A) have equal effusion rates
• B) have equal average molecular velocities
• C) have equal average molecular kinetic energies
• D) occupy equal volumes

9. In a sample of air at STP, the ratio of the root-mean-square velocity of O₂ to that of N₂ , that is u_rms  (O₂) / u_rms (N₂), is equal to:

• A) 0.88
• B) 0.94
• C) 1.00
• D) 1.07

10. A gas of twice the molecular weight as CO will pass through a small hole how much faster than CO ?

• A) 1/2 as fast
• B) 2 times as fast
• C) 2^1/2 as fast
• D) (1 / 2^1/2 ) as fast

11. If a gas's volume is doubled but the temperature remains constant:

• A) the pressure stays the same
• B) the molecules move faster
• C) the kinetic energy increases
• D) the molecules move slower
• E) none of these answers

12. When 8.21 L of C₃H₈ (g) burn in oxygen, how many liters of oxygen are consumed? All gas volumes are measured at thesame temperature and pressure but not at STP.

• A) 57.5 L
• B) 41.0 L
• C) 1.17 L
• D) 1.64 L

E) none of these answers

13. In the reaction CH₄ + 2O₂ -> CO₂ + 2H₂O, how many liters of O₂ react with 5.0 liters of CH₄ ? All gas volumes are measured at the same temperature and pressure but not at STP.

• A) 5.0/22.4
• B) 5.0(2/1)
• C) 5.0
• D) 5.0(1/2)
• E) none of these answers

14. In the reaction 2Na + 2H₂O -> 2NaOH + H₂ , how many liters of hydrogen at STP are produced from 50.0 grams of sodium (Na = 23.0, O = 16.0, H = 1.0 g/mol) ?

• A) (55.0/18.0)(22.4)
• B) (50.0/23.0)(22.4/2)
• C) (50.0/23.0)(2)(22.4)
• D) (50.0/23.0)(22.4)
• E) none of these answers

15. In the reaction Fe₂O₃ + 3H₂ -> 2 Fe + 3 H₂O, how many moles of iron can be produced using 17.4 liters of hydrogen at STP?

• A) (17.4/22.4)(2/3)
• B) (17.4/22.4)(3/2)
• C) (17.4)(2/3)
• D) (17.4/22.4)
• E) none of these

16. Two containers are connected by an open tube. One container (A) is at 300 K, the other (B) is at 600 K. These two containers must have:

• A) equal number of moles
• B) greater pressure in A than B
• C) greater pressure in B than A
• D) equal volume
• E) none of these answers

17. If a liter of CO₂ is compared to a liter of H₂, both at 25 ^oC and one atmosphere pressure, then:

• A) the CO₂ and H₂ molecules have the same average speed
• B) there are more H₂ molecules than CO₂ molecules
• C) the average kinetic energy of the CO₂ molecules is greater than that of the H₂ molecules
• D) the CO₂ molecules are on the average moving more slowly than the H₂ molecules
• E) the mass of one liter of CO₂ equals the mass of one liter of H₂

18. The energy of molecules of a gas:

• A) is dependent on concentration
• B) is distributed over a wide range at constant temperature
• C) is the same for all molecules at constant temperature
• D) increases with a decrease in temperature
• E) increases with an increase in pressure

19. A 1.37 L vessel contains He at a temperature of 24.5 ^oC and a pressure of 205 mmHg. A 721 mL vessel contains Ne at a temperature of 36.2 ^oCand a pressure of 0.185 atm. Both of these gases are placed in a 2.00 L vessel at 302 K. What is the final pressure (in atm) in the 2.00 L vessel?

20. 53.5 g of an ideal gas of molecular weight = 30.5 g/mol are confined at a pressure of 133 mmHg. The density of the gas is 0.228 g/L. Compute the temperature of the gas in degrees Celsius.

21. The complete combustion of octane, a component of gasoline, is represented by the equation:

2C₈H₁₈ (l) + 25O₂ (g) -> 16CO₂ (g) + 18H₂O(l)

How many liters of CO₂ (g), measured at 63.1 ^oC and 688 mmHg, are produced for every gallon of octane burned? (1 gal = 3.785 L; density of C₈H₁₈ (l) = 0.703 g/mL)

22. A 500.0 mL sample of O₂ (g) is at 780 mmHg and 30 ^oC. What will be the new volume if, with the pressure and amount of gas held constant, the temperature is decreased to -15 ^oC?

23. What volume of acetylene gas, C₂H₂ , would be required at STP to obtain a 200.0 g C₂H₂ sample?

24. A sample of N₂ (g) effuses through a tiny hole in 19.0 s. How long would it take for a sample of N₂O₂ (g) to effuse under the same conditions?

25. Calculate the height of a column of liquid glycerol (d = 1.26 g/cm³), in meters, required to exert the same pressure as 4.91 m of water.

Convert each pressure to the equivalent pressure in standard atmospheres:

26) 1250 mmHg

27) 8.50 kg/cm s²

28) 421 kPa

29) 27.5 inches of mercury

30) 780 Torr

31. A 40.2 L constant-volume cylinder containing 2.21 mol He is heated until the pressure reaches 4.2 atm. What is the final temperature?

32. A sample of gas has a volume of 2.5 L at 30 ^oC and 720 mmHg. What will be the volume of this gas at 22 ^oC and 750 mmHg?

33. A gaseous hydrocarbon weighing 0.290 g occupies a volume of 125 mL at 25 ^oC and 760 mmHg. What is the molar mass of this compound?

34. What pressure must be applied to N₂ (g) to obtain a density of 2.00 g/L at 25 ^oC?

35. Calculate the volume of H₂ (g) expressed at STP, required to react with 3.00 L of CO(g) at STP in the following reaction:
3CO(g) + 7H₂ (g) -> C₃H₈ (g) + 3H₂O(l)

36. Consider the following reaction: N₂ (g) + 3H₂ (g) -> 2NH₃(g)
What volume of NH_{3 (g)} can be produced from 200.0 L of H_{2 (g)} if the gases are measured at 350 ^oC and 400 atm pressure?

37. Calculate u_rms , in m/s, for H₂ (g) molecules at 25^oC.

38. What is the ratio of the diffusion rates of Cl₂ and O₂?

39. The measured pressure of a van der Waals gas compared to an ideal gas is:

• A) lower, because of the intermolecular forces
• B) lower, because the gases expand
• C) higher, because the molecules occupy space
• D) higher, because the molecules repel each other

40. Gases tend to behave ideally at

• A) low temperature and low pressure
• B) low temperature and high pressure
• C) high temperature and low pressure
• D) high tempertaure and high pressure

41. What is the volume, in L, occupied by a mixture of 16.0 g Ne(g) and 42.0 g Ar(g) at 15.0 atm pressure and 25 ^oC?

42. A 4.0 L sample of N₂ (g) at 760 mmHg is compressed, at constant temperature, to 3.2 atm. What is the final gas volume?