Chemistry 222 Exam II Review: Gas Laws, Reactions, and Intermolecular Forces

Explore questions related to gas volume changes with pressure, gas density comparisons, stoichiometry in gas reactions, gas velocity comparisons, pressure comparison between gases, boiling point predictions based on intermolecular forces, and ranking molecules based on intermolecular forces.

• Chemistry
• Gas Laws
• Stoichiometry
• Intermolecular Forces

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1. Chemistry 222 Exam II Review Chapters 9, 10 and 11 Chemistry 222 Professor Michael Russell Last update: 4/29/24 MAR MAR

2. A sample of gas has a volume of 222 mL at 695 mm Hg and 0 C. What would be the volume of this same sample of gas if it were measured at 333 mm Hg and 0 C? A.894 mL B.463 mL C.657 mL D.359 mL E.-155 mL MAR MAR

3. Gas density: Which has the greatest density at 25 C and 1.00 atm pressure? A.O2 B.N2 C.H2 D.CO2 E.Xe 32 g/mol 28 g/mol 2 g/mol 44 g/mol 131 g/mol MAR MAR

4. Diborane reacts with O2to give boric oxide and water vapor: B2H6(g) + 3 O2(g) B2O3(s) + 3 H2O(g) If 1.5 L of B2H6is mixed with O2, what volume of O2is required for reaction? Assume constant T and P. A.1.5 L B.4.5 L C.0.50 L D.6.0 L E.0.0 L MAR MAR

5. Diborane, B2H6, burns in air according to the equation: B2H6(g) + 3 O2(g) B2O3(s) + 3 H2O(g) There are three gases involved in the reaction above. Place them in order of increasing velocity. A.B2H6< O2< H2O B.O2< B2H6< H2O C.H2O < B2H6< O2 D.O2< H2O < B2H6 MAR MAR

6. Equal masses of helium and neon are placed in separate containers of equal V at the same T. Compare the pressures of the gases. A.P(He) > P(Ne) B.P(Ne) > P(He) C.P(He) = P(Ne) D.Too much pressure! MAR MAR

7. Using intermolecular forces, the predicted order of decreasing boiling points for the following substances is A.CH3OH > CH4> H2 B.CH3OH > H2> CH4 C.CH4> CH3OH > H2 D.CH4> H2> CH3OH E.H2> CH4> CH3OH MAR MAR

8. Rank the following molecules in order of increasing intermolecular forces: SO2, NaCl, CH3OH, He A.NaCl < He < SO2 < CH3OH B.He < CH3OH < SO2 < NaCl C.He < SO2 < CH3OH < NaCl D.He < SO2 < NaCl < CH3OH MAR MAR

9. When KCl dissolves in water, what types of intermolecular bonds are formed? A.ion-ion B.ion-dipole C.hydrogen bonds D.ion-ion forces and H-bonds E.matrimony bonds MAR MAR

10. Which of the following should have the highest Hvap? A.F2 B.CH3OH C.H2O D.NH3 E.all have the same Hvap value MAR MAR

11. The unit cell for a compound of copper and oxygen is illustrated here. All the grey copper atoms are within the unit cell. Determine the formula of the compound. A.CuO B.Cu2O C.CuO2 D.Cu2O3 E.Cu4O9 MAR MAR

12. Below is a phase diagram for O2. What is the name of the point at P = 2 mm Hg and T = 54.34 K? A. normal freezing point B. triple point C. normal boiling point D. critical point E. freak out point MAR MAR

13. At right is a phase diagram for O2. Which statement is correct regarding the densities of solid and liquid O2at the same temperature? A.The density of liquid O2is 1.426 g/cm3whereas the density of solid O2is 1.149 g/cm3. B.The density of solid O2is 1.426 g/cm3whereas the density of liquid O2is 1.149 g/cm3. C.The densities of solid and liquid O2are the same. MAR MAR

14. Below is a phase diagram for O2. In what phase is oxygen found at a pressure of 1 mmHg and a temperature of 55 K? A. solid B. liquid C. vapor D. plasma MAR MAR

15. Calculate the energy required to convert 1.00 L of liquid ethanol at 25.0 C to a gas at 78.3 C. Constants for ethanol: density = 0.7849 g/mL molar mass = 46.08 g/mol boiling point = 78.3 C heat capacity = 2.44 J/g K heat of vaporization = 38.56 kJ/mol A. -329 kJ B. 329 kJ C. -759 kJ D. 759 kJ E. 0 KJ MAR MAR

16. You dissolve 92.0 grams of CH3CH2OH, ethanol, in 270 g of water. What is the mole fraction of ethanol in the solution? A.2.0 B.0.12 C.0.067 D.0.0083 E.0 MAR MAR

17. You dissolve 92.0 grams of CH3CH2OH, ethanol, in 270. g of water. What is the weight percent of ethanol in the solution? A.34.1 % B.17.0 % C.25.4 % D.74.8 % E.100. % MAR MAR

18. You dissolve 92.0 grams of CH3CH2OH, ethanol, in 270. g of water. What is the molality of ethanol in the solution? A.341 m B.170. m C.0.341 m D.7.41 m E.18.0 m MAR MAR

19. You dissolve 92.0 grams of CH3CH2OH, ethanol, in 270. g of water, and the density of the solution is 0.9780 g/mL. What is the molarity of ethanol in the solution? A.0.370 M B.2.00 M C.7.42 M D.3.05 M E.5.41 M MAR MAR

20. An aqueous solution of ethanol (CH3CH2OH) has a solution density of 0.9163 g/mL and a concentration of 0.801 M. What is the mole fraction of ethanol in the solution? A.0.911 B.1.1111 C.0.9839 D.0.0161 E. 4.03 MAR MAR

21. The Henry's Law constant for N2 in water at 53 C is 8.4 x 10-7M/mm Hg, and the vapor pressure of water at 53 C is 107 torr. Find the equilibrium concentration of N2 in water if the total pressure equals 1 atm. A.5.5 x 10-4M B.9.0 x 10-5M C.6.4 x 10-4M D.3.2 x 10-5M E.42 M MAR MAR

22. 0.0400 mol of I2(10.1 g) is dissolved in 1.96 mol of CCl4(300 g) at 65 C. Given that the vapor pressure of pure CCl4is 504 mm Hg at this temperature, what is the vapor pressure of the CCl4over this solution? A.504 mm Hg B.514 mm Hg C.494 mm Hg D.10.1 mm Hg E.Too much pressure! MAR MAR

23. What mass of ethylene glycol (HOC2H4OH, molar mass = 62.0 g/mol) must be added to 125 g of water to raise the boiling point by 1.00 C? (kbp(H2O) = +0.512 C/m) A.1.95 g B.0.244 g C.15.1 g D.31.0 g E.0 g MAR MAR

24. Which water-based solution is expected to have the higher boiling point? A.0.10 molal NaCl B.0.15 molal sugar C.both the same D.not enough information MAR MAR

25. 29.3 g of NaCl (molar mass = 58.5 g/mol) is dissolved in 500. grams water. What is the boiling point of this solution? (kbp(H2O) = +0.512 C/m) A.100.512 C B.98.976 C C.101.02 C D.1.024 C E.104 K MAR MAR

26. Erythritol occurs naturally in algae and fungi. A solution of 2.50 g of erythritol in 50.0 g of water freezes at -0.762 C. What is the molar mass of the compound? (kfp(H2O) = -1.86 C/m) A. 26.9 g/mol B. 35.5 g/mol C. 122 g/mol D. 224 g/mol E. 0.0100 g/mol MAR MAR

27. Insulin (20.0 mg) dissolved in 5.00 mL of water at 300. K provides an osmotic pressure of 12.5 mm Hg. What is the molar mass of insulin? A. 18.0 g/mol B. 42.0 g/mol C. 3980 g/mol D. 6010 g/mol E. 12,100 g/mol MAR MAR

28. End of Review - good luck with your studying! Need more practice? Practice Problem Sets (online) Concept Guides (Companion and online) Chapter Guides (online) End of Chapter Problems in Textbook (every other question has answer at end) Good luck with your studying! MAR MAR