Chemistry 121 Chapters 7& 8 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A sample of carbon dioxide occupies 22.4 L at STP. Which of the following statements apply to the sample? a. The sample contains 6.02 10 23 atoms. b. The sample contains 6.02 10 23 atoms of oxygen. c. The sample contains 6.02 10 23 molecules. d. None of the above is correct. 2. What is the volume occupied by a 8.00 gram sample of molecular oxygen at STP? a. 5.60 L c. 22.4 L b. 11.2 L d. 44.8 L 3. Standard temperature and pressure are which of the following? a. 0 C and 1 atm c. 273 K and 1 atm b. 32 F and 1 atm d. all of these 4. Which of the following is a mathematical statement of the ideal gas law? a. PV = n/rt c. V = np/rt b. PV = nrt d. PV = RT/n 5. A vessel under 2.015 atm pressure contains nitrogen, N 2, and water vapor, H 2 O. The partial pressure of N 2 is 1.908 atm. What is the partial pressure of the water vapor? a. 0.107 atm c. 2.015 atm b. 1.908 atm d. 3.923 atm 6. According to the kinetic molecular theory, which of the following is not true? a. The average kinetic energy of gas particles is proportional to the Celsius temperature. b. Gas molecules are assumed to have no volume. c. Gas pressure is caused by collisions between gas molecules and the container walls. d. None, all of the above are true. 7. The term solution is synonymous with which of the following? a. compound c. heterogeneous mixture b. element d. homogeneous mixture 8. Which of the following cannot serve as a solvent in a solution? a. a gas c. a solid b. a liquid d. None, all can serve as solvents. 9. A student is preparing a sugar water solution to make rock candy. When the student continues to add sugar to the solution the sugar dissolves. Which kind of solution does the student have? a. a saturated solution c. an unsaturated solution b. a supersaturated solution d. We cannot tell. 10. When considering the solubility of a particular solute in a particular solvent the term like dissolves like generally refers to which of the following properties? a. formula weight c. both a and b b. molecular polarity d. neither a nor b 11. Water is generally a good solvent for which of the following types of compounds? a. nonpolar compounds c. both a and b b. polar compounds d. neither a nor b
12. Which of the following is true regarding the solubility of gases? a. Solubility always decreases as pressure increases. b. Solubility always increases as pressure increases. c. Solubility usually decreases as pressure increases. d. Solubility usually increases as pressure increases. 13. Which of the following is the definition of molarity? a. moles of solute/1000 grams of solvent b. moles of solute/liter of solution c. moles of solute/liter of solvent d. moles of solvent/1000 grams of solute 14. If we wish to prepare 250. ml of 0.200 M BaCl 2, how much solid is BaCl 2 is needed? a. 4.17 g c. 10.4 g b. 5.21 g d. 20.8 g 15. If we wish to prepare a 0.50 M solution of NaCl, how much water must be added to 1.0 mole of NaCl? a. 2.0 mol b. 2.0 L c. 2.0 10 3 g d. Enough water to make 2.0 L of solution. 16. What is the mass of NaCl in a 0.500 L bottle of 2.00 M NaCl? a. 29.3 g c. 117 g b. 58.5 g d. 234 g 17. Which of the following solutions will have the higher electrical conductivity? a. 0.1 M NaCl c. Both a and b have the same conductivity. b. 0.2 M NaCl d. Neither conducts electricity. 18. Which of the following is true of methanol, CH 3 OH, when it dissolves in water? a. It dissociates into ions. b. It forms covalent bonds with water. c. It forms hydrogen bonds with water. d. None of the above, methanol does not dissolve in water. 19. Water is likely to be a poor solvent for which types of molecules? a. molecules which can form hydrogen bonds b. nonpolar molecules c. polar molecules d. None, water is considered a universal solvent. 20. Thermal pollution generally means refers to which of the following? a. the decrease in the O 2 content of warm water as compared to cold water b. the increase in the O 2 content of cold water as compared to warm water c. both a and b d. neither a nor b 21. A certain wine contains 0.0100 M NaHSO 3 as a preservative. What mass of NaHSO 3 is in a 750 ml bottle of this wine? a. 0.39 g c. 0.78 g b. 0.70 g d. 1.5 g 22. How many moles of solute are contained in 500. ml of 0.50 M KCl? a. 0.25 c. 1.0 b. 0.50 d. 2.0
23. What volume of 12.0 M HCl must be used to make 300. ml of 0.600 M HCl? a. 1.50 ml c. 15.0 ml b. 2.40 ml d. 24.0 ml 24. Which of the following is true of electrolytes? a. All electrolytes have mobile ions. b. All electrolytes contain equal numbers of cations and anions. c. both a and b d. neither a nor b 25. Which of the following is true of all strong electrolytes? a. They are all ionic compounds. c. both a and b b. They all dissociate completely. d. neither a nor b Consider the following graph. 26. Approximately what mass of A will dissolve in 100 ml of water at 75 C? a. 25 g c. 55 g b. 40 g d. 70 g 27. Which substance exhibits solubility behavior that is similar to that of a gas? a. A b. B c. C d. None of the substances listed show this behavior. 28. Which of the following generally occurs as temperature increases? a. Solubility of a solid solute decreases. b. Solubility of a solid solute increases. c. Solubility of a solid solute remains the same. d. Molarity of a solid solute doubles. 29. Oxygen in nitrogen is an example of which solute-solvent combination? a. gas-liquid c. gas-solid b. liquid-gas d. gas-gas
30. Convert the pressure 2.50 atm to kpa. a. 1 kpa c. 760 kpa b. 253 kpa d. 1000 kpa 31. Which of the following compounds is insoluble in water? a. CaCO 3 c. Ca(NO 3 ) 2 b. CaCl 2 d. Ca(C 2 H 3 O 2 ) 2 32. When a solution of ammonium chloride, NH 4 Cl, is added to a solution of lead(ii) nitrate, Pb(NO 3 ) 2, a white precipitate of lead chloride, PbCl 2, forms. Which of the following is the total ionic equation for this reaction? a. 2 NH 4 Cl(aq) + Pb(NO 3 ) 2 (aq) PbCl 2 (s) + 2 NH 4 NO 3 (aq) b. 2 NH + 4 (aq) + 2 Cl-(aq) + Pb 2+ (aq) + 2 NO 3 -(aq) PbCl 2 (s) + 2 NH + 4 (aq) + 2 NO 3 -(aq) c. Pb 2+ (aq) + 2 Cl-(aq) PbCl 2 (s) d. Pb 2+ (aq) + Cl 2 2 -(aq) PbCl 2 (s) 33.Which of the following sulfides is soluble in water? a. Ag 2 S c. K 2 S b. FeS d. PbS Part II. Short Answer. Please show all work. Only one point will be given for the correct answer. Make sure all calculated values have units written after the number and are reported to the correct number of significant digits. Equations are given below: M 1 V 1 = M 2 V 2 P 1 V 1 = P 2 V 2 PV = nrt molarity, M = n/v T 1 T 2 R = 0.0821 L atm/mol K 1 kg = 1000g 1 L = 1000 ml 1 atm = 760 torr = 760 mmhg = 101.3 kpa K = C + 273 1. A diver at a depth of 20 m inhales 0.50 L of an air mixture at a pressure of 303.9 kpa. If the diver holds his breath and quickly swims to the surface where the pressure is 1.00 atm, calculate the new volume of air in his lungs. Explain why doing this would be dangerous. Assume conditions of constant temperature. 2. What is the molarity of 5.00 g of potassium chloride in 750.0 ml of solution?
3. How much concentrated hydrochloric acid (12.4 M) would be needed to prepare 100.0 ml of 3.00 M hydrochloric acid? 4. If you were to take a volleyball scuba diving with you what would be its new volume if it started at the surface with a volume of 2.00L, under a pressure of 752.0 mmhg and a temperature of 20.0 C? On your dive you take it to a place where the pressure is 2943 mmhg, and the temperature is 0.245 C. 5. A 10.0 gram chunk of dry ice (solid CO 2 ) changes to gas. What is the volume of that gas measured at 27 C and 740 mmhg? 6. If 10.0 ml of 0.020 mol/l HCl (aq) react exactly with 12.0 ml of Ba(OH) 2(aq), find the molar concentration of the barium hydroxide solution. 7. If 200.0 ml of 0.100 mol/l AgNO 3 completely reacts with copper, what mass of silver will be produced?
8. A solution of 100.0 ml of 0.200 M KOH solution is added to 200.0 ml of a 0.150 M nickel (II) nitrate solution. a. Write the balanced chemical equation for the reaction that occurs. b. What precipitate forms? c. What is the limiting reactant? d. How many grams of the precipitate form?