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Acid Base Equilibrium Pretest

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Acid Base Equilibrium Pretest Name: ________________________ Class: ___________________ Date: __________ ID: A Acid Base Equilibrium PreTest Multiple Choice Identify the choice that best completes the statement or answers the question. 1. If a reaction is reversible, what are the relative amounts of reactant and product at the end of the reaction? a. no reactant; all product b. no product; all reactant c. some product; some reactant d. The relationship between reactants and products cannot be determined. 2. What happens to a reaction at equilibrium when more reactant is added to the system? a. The reaction makes more products. b. The reaction makes more reactants. c. The reaction is unchanged. d. The answer cannot be determined. 3. Which of the changes listed below would shift the following reaction to the right? 4HCl(g) + O2 (g) 2Cl2 (g) + 2H2 O(g) a. addition of Cl2 b. removal of O2 c. increase of pressure d. decrease of pressure 4. What is the effect of adding more water to the following equilibrium reaction? CO2 + H2 O H2 CO3 a. More H2 CO3 is produced. b. CO2 concentration increases. c. The equilibrium is pushed in the direction of reactants. d. There is no effect. 8 5. In an equilibrium reaction with a Keq of 1 10 , the ____. a. reactants are favored b. reaction is spontaneous c. the products are favored d. reaction is exothermic 7 6. The Keq of a reaction is 4 10 . At equilibrium, the ____. a. reactants are favored b. products are favored c. reactants and products are present in equal amounts d. rate of the forward reaction is much greater than the rate of the reverse reaction 7. When an acid reacts with a base, what compounds are formed? a. a salt only b. water only c. metal oxides only d. a salt and water 8. Which of these is an Arrhenius base? a. LiOH b. NH3 c. H2 PO4 d. CH3 COOH 9. What type of acid is sulfuric acid? a. monoprotic b. diprotic c. triprotic d. none of the above 10. Which of the following reactions illustrates amphoterism? + - + - + - + - a. H2O + H2O H3O + OH b. NaCl Na + OH c. HCl + H2O H3O + Cl d. NaOH Na + OH 11. What are the acids in the following equilibrium reaction? CN + H2 O HCN + OH a. CN , H2 O b. H2 O, HCN c. CN , OH d. H2 O, OH 12. If the hydrogen ion concentration of a solution is 1010 M, is the solution acidic, alkaline, or neutral? a. acidic b. alkaline c. neutral d. The answer cannot be determined. 1 Name: ________________________ ID: A 13. What is pH? a. the negative logarithm of the hydrogen ion concentration b. the positive logarithm of the hydrogen ion concentration c. the negative logarithm of the hydroxide ion concentration d. the positive logarithm of the hydroxide ion concentration 14. An indicator is what type of compound? a. oxidizing agent b. weak base or acid c. strong base or acid d. salt 15. With solutions of strong acids and strong bases, the word strong refers to ____. a. normality b. molarity c. solubility d. degree of ionization 16. A 0.12M solution of an acid that ionizes only slightly in solution would be termed ____. a. concentrated and weak b. strong and dilute c. dilute and weak d. concentrated and strong 17. In a titration, when the number of moles of hydrogen ions equals the number of moles of hydroxide ions, what is said to have happened? a. The equivalence point has been reached. b. The end point has been reached. c. The point of neutralization has been reached. d. The titration has failed. 18. Which of the properties listed below is not characteristic of an acid? a. a sour taste b. a slippery feel c. the ability to conduct an electric current d. reactivity with metals 19. Acetic acid is found in a. vinegar. b. the stomach. c. antacids. d. oranges. 20. Which of the following is a Brønsted-Lowry base? + a. HCl b. HCO3 c. H3O d. H3PO4 21. What is the correct acid name for an aqueous solution of HClO4? a. hypochlorous acid b. chlorous acid c. chloric acid d. perchloric acid 22. A substance that increases the concentration of OH ions in an aqueous solution is known as a(n) a. Arrhenius acid. b. Arrhenius base. c. Lewis acid. d. Lewis base. 23. In a Brønsted-Lowry acid-base reaction, what are transferred from one reactant to another? a. electrons b. water molecules c. protons d. OH ions 24. How many protons per molecule can a monoprotic acid donate? a. one b. two c. three d. zero 25. HCl is a strong acid. When it combines with water, the conjugate of HCl will be a a. weak base. b. weak acid. c. strong base. d. strong acid. 26. What is the net ionic equation for the neutralization rxn. between HNO3(aq) + KOH(aq) ? - + + + - + - + a. NO3 + K KNO3 b. H3O + OH 2H2O(l) c. H3O + NO3 + K + OH NO3 + K + 2H2O(l) d. HNO3 + KOH KNO3 + H2O(l) 27. Aqueous solutions of most bases contain a. hydroxide ions and cations. b. hydroxide ions and anions. c. hydrogen ions and anions. d. hydrogen ions and cations. 2 Name: ________________________ ID: A 28. A strip of pH paper a. gives a quick approximation of pH. b. is a precise measure of pH. c. shows very little color change over a wide pH range. d. must be calibrated with a pH meter before it is used. 29. A pH meter measures the pH of a solution by measuring the a. amount of charge on the hydronium ion. b. color of the solution. c. concentration of the solution. d. voltage difference between two electrodes in the meter’s probe. 30. At the end point of a titration using an acid-base indicator, a. the color of the acid-base indicator should stay the same. b. the pH of the solution should change abruptly. c. the color of the acid-base indicator should change. d. Both (b) and (c) 31. A standard solution a. contains a precisely measured amount of solute. b. must be compared with a solution of primary standard before use. c. is the known solution used in a titration. d. All of the above 32. Universal indicators a. are mixtures of several indicator solutions. b. are pure substances. c. have very brief color-change intervals. d. work well only for acidic solutions. 33. A useful pH range for an indicator in neutralizations involving strong acids and weak bases is a. 1.2 to 3.0. b. 3.1 to 4.6. c. 6.0 to 7.6. d. 9.5 to 11.0. 34. What is the equilibrium expression for the following equation? 3+ Fe(OH)3(aq) Fe (aq) + 3OH (aq) 3+ 3+ 3 [Fe ][OH ] [Fe ][OH ] [Fe(OH)3] [Fe(OH)3] a. b. c. d. [Fe(OH)3] [Fe(OH)3] [Fe3+][OH]3 [Fe3+][OH] + 2 35. Consider the reaction represented by the equation Ag2SO4(aq) 2Ag (aq) + SO4 (aq). You can shift the equilibrium to favor the reverse reaction by adding a. CaCl2. b. AgNO3. c. Na2SO4. d. Both (b) and (c) 36. A chemical reaction that is at equilibrium always has a. a high Keq value. b. a forward reaction rate that equals the reverse reaction rate. c. equal concentrations of reactants and products. d. Both (a) and (b) 37. What is the value of Kw? a. 1 1014 b. 1 1014 c. 1 107 d. 14 1014 38. Which of the following is a conjugate acid-base pair in the reaction represented by the equation below? H2PO4 + H2O H3PO4 + OH a. H2PO4 and H2O b. H2PO4 and OH c. H2PO4 and H3PO4 d. None of the above 39. What is the effect on concentration if more CO(g) is added to the following equilibrium system? 2CO(g) + O2(g) 2CO2(g) a. [CO2] increases and [O2] decreases. b. Both [CO2] and [O2] increase. c. Both [CO2] and [O2] decrease. d. Both [CO2] and [O2] remain the same. 3 Name: ________________________ ID: A 40. A very high value for K indicates that a. reactants are favored. b. products are favored. c. equilibrium is reached slowly. d. equilibrium has been reached. 41. The equilibrium constant for the gas phase reaction 2NH3 (g) N2 (g) + 3H2 (g) is Keq = 230 at 300°C. At equilibrium, __________. a. products predominate b. reactants predominate c. roughly equal amounts of products and reactants are present d. only products are present e. only reactants are present 42. Phosphorous trichloride and phosphorous pentachloride equilibrate in the presence of molecular chlorine according to the reaction: PCl3 (g) + Cl2 (g) PCl5 (g) An equilibrium mixture at 450 K contains PPCl3 = 0.202 atm, PCl2 = 0.256 atm, and PPCl5 = 3.45 atm. What is the value of Kp at this temperature? a. 66.7 b. 1.50 10-2 c. 1.78 10-1 d. 2.99 e. 7.54 43. What is the pH of a 0.015 M aqueous solution of barium hydroxide? a. 12.48 b. 12.25 c. 1.82 d. 10.41 e. 1.52 44. Which of the following is true about chemical equilibrium? a. It is microscopically and macroscopically static. b. It is microscopically and macroscopically dynamic. c. It is microscopically static and macroscopically dynamic. d. It is microscopically dynamic and macroscopically static. e. None of these are true about chemical equilibrium. 45. The value of the equilibrium constant, K, is dependent on: I. the temperature of the system II. the nature of the reactants and products III.
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