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1 (name) Place the letter of the correct answer in the place provided. Work must be shown for non-multiple choice problems 1. According to Raoults Lab the change in the vapor pressure of a solution containing a nonvolatile solute is directly proportional to the a. mole fraction solute b. mole fraction solvent c. molarity of the solution d. molality of the solution e. osmotic pressure of the solvent 2. How many atoms per unit cell are there in each of the following cubic lattice types? simple cubic body-centered cubic face-centered cubic (a) (b) (c) (d) Arrange the following in order of increasing boiling point (lowest to highest) NH 3, PH 3, AsH 3, SbH 3, 4. Potassium bromide reacts with chlorine in aqueous solution to form the tribromide ion: KBr(aq) + Br 2 (aq) --> KBr 3 (aq) What would happen if we added CCl 4 to this reaction? a. The KBr would tend to dissolve in the CCl 4 layer. b. The Br 2 would tend to dissolve in the CCl 4 layer. c. Both KBr and Br 2 would dissolve in the CCl 4 layer. d. Neither KBr nor Br 2 would dissolve in the CCl 4 layer.

2 e. Because CCl 4 and water are miscible, no distinct CCl 4 layer would form. 5. The ease with which the charge distribution in a molecule can be distorted by an external electrical field is called" a. the polarizability b. the electronegativity c. hydrogen bonding d. viscosity e. polarity 6. Under ordinary conditions a substance will sublime rather than melt if a. its triple point occurs at a pressure above atmospheric pressure b. its triple point occurs at a pressure below atmospheric pressure c. its critical temperature is above its normal boiling point d. its critical point occurs at a temperature above room temperature e. its critical point occurs at a temperature above atmospheric pressure 7. What are the intermolecular forces responsible for the dissolution of gaseous hydrogen in water? a. dipole-dipole b. dipole-induced dipole c. ion-dipole d. London dispersion forces e. hydrogen bonding 8. Which of the following should be miscible in water? a. bromine (Br 2 ) b. octane (CH 3 (CH 2 ) 6 CH 3 ) c. methanol CH 3 OH d. benzene (C 6 H 6 ) e. pentane (CH 3 (CH 2 ) 3 CH 3 9. Which of the following statements are correct? 1. A liquid boils when its vapor pressure is equal to the pressure above its surface. 2. Above the critical pressure, only the solid phase of a pure substance can exist. 3. The gas, liquid, and solid phases can all coexist at the critical point. a. 1 only b. 2 only c. 3 only d. 1 and 2 e. 1 and Which one of the following substances will exhibit dipole-dipole intermolecular forces? a. Kr b. N 2 c. CO 2 d. CCl 4 e. CO

3 11. Which of the following statements concerning the attraction between ions and polar solvent molecules are correct? 1. The larger the ion charge, the greater the attraction. 2. The attractive force increases as ionic radii increases. 3. The greater the dipole (of the solvent molecule), the greater the attraction. a. 1 only b. 2 only c. 3 only d. 1 and 3 e. 1, 2, and The solubility of nitrogen gas in water at a nitrogen pressure of 1.0 atm is 6.9x10-4 M. The solubility of nitrogen in water at a nitrogen pressure of 0.80 atm is M. 13. Which of the following aqueous solutions should have the lowest freezing point? a. pure H 2 O b. 1 m CaBr 2 c. 1 m NH 3 d. 1 m NaNO 3 e. 1 m C 6 H 12 O What mass of NaCl must be dissolved in 50.0 grams of water to lower the freezing point to -2.00ºC? The freezing point depression constant, K fp, for water is -1.86ºC/m.

4 15. The melting point of pure benzene is K and the molal freezing point depression constant is 4.90 K/molal. When 4.20 g of an unknown non-electrolyte is added to 100 g of benzene, the freezing point of the solution is K. What is the molecular weight of the unknown? 16. Equal masses of water and ethylene glycol are mixed. What is the concentration of aqueous ethylene glycol in units of molality? The molar mass of water and ethylene glycol are g/mol and g/mol, respectively. 17. The vapor pressure of pure water at 35ºC is 42.2 mm Hg. What is the vapor pressure of a mixture of 15 g sucrose (C 12 H 22 O 11, molar mass g/mol) and 85 g water? 18. The most likely van't Hoff factor for a 1.00 M CaI 2 solution is. NOTE: we are asking for a real solution, not an ideal solution. a b c d e. 3.29

5 19. Determine the molecular weight of an unknown non-electrolyte. 1.0 g of the unknown was dissolved in 25.0 g of acetic acid. The solution boiled at o C. K b (HC 2 H 3 O 2 ) = 2.93 o C/m and pure acetic acid boils at o C. 20. Commercial concentrated aqueous ammonia is 28% NH 3 by mass and has a density of 0.90 g/ml. Calculate the mole fraction of NH 3 in this solution. Bonus Question (6 pts, highest possible exam score = 100 pts): Draw the phase diagram for carbon dioxide, label all axes, the 3 phase regions, the triple pt and the critical pt. and draw a 1 atm isobar.

CHM151 Quiz Pts Fall 2013 Name: Due at time of final exam. Provide explanations for your answers.

CHM151 Quiz Pts Fall 2013 Name: Due at time of final exam. Provide explanations for your answers. CHM151 Quiz 12 100 Pts Fall 2013 Name: Due at time of final exam. Provide explanations for your answers. 1. Which one of the following substances is expected to have the lowest melting point? A) BrI B)