Honors Chemistry Name _____________________________________ Chapter 14/15: Acids/Bases Review Worksheet II Date _____/_____/_____ Period _____ 1. What volume of 0.050 M NaOH(aq) will exactly neutralize 100.0 mL of 0.075 M HBr solution? a. 100.0 mL c. 6.6 x 10-3 mL e. 120 mL b. 7.5 mL d. 150 mL NaOH + HBr NaBr + HOH 100.0 mL 1L 1000 mL 0.075 mole HBr 1L 1 mole NaOH 1 mole HBr 1L 0.050 mole NaOH 1000 mL 1L = 150 mL 2. What volume of 0.200 M H2SO4(aq) would exactly neutralize 2.00 L of 1.0 x 10-3 M Al(OH)3? a. 6.7 mL b. 10 mL c. 15 mL d. 1.00 L e. 75 mL 3 H2SO4 + 2 Al(OH)3 6 HOH + Al2(SO4)3 2.00 L 1.0 x 10-3 mole Al(OH)3 1L 3 mole H2SO4 2 mole Al(OH)3 1 LH2SO4 0.200 mole H2SO4 1000 mL 1L = 15 mL 3. What is the hydroxide concentration in a solution which results from pouring 100 mL of 0.010 M HCl together with 200 mL of 0.030M Ca(OH)2(aq) solution? Assume that the liquid volumes are additive. a. 0.020 M c. 0.0367 M e. 0.030 M b. 0.0183 M d. 0.060 M 2 HCl + Ca(OH)2 2 HOH + CaCl2 0.1 L HCl 0.010 mole HCl 1L 0.2 L Ca(OH)2 1 mole H+1 1 mole HCl 2 mole (OH)-1 1 mole Ca(OH)2 0.030 Ca(OH)2 1L = 0.001 mole H+1 = 0.012 mole (OH)-1 0.012 mole (OH)-1 - 0.001 mole H+1 0.011 mole (OH)-1 0.011 mole (OH)-1 = 0.0367 M 0.3 L 4. Write the conjugate acid for each of the following: a. HPO4-2 b. NO2-1 c. HS-1 H2PO4-1 HNO2 H2S d. S-2 HS-1 5. In standardizing an HCl solution of unknown concentration, 21.50 mL of HCl solution are found to reach the endpoint in a titration with 4.086 g of Na2CO3. (MM = 106.0 g/mol) What is the molarity of the HCl solution? a. 1.79 M b. 3.58 M c. 0.896 M d. 3.6 x 10-3 M 2 HCl + Na2CO3 2 NaCl + H2CO3 4.086 g Na2CO3 1 mole Na2CO3 106.0 g Na2CO3 2 mole HCl 1 mole Na2CO3 = 0.07709 mole Na2CO3 0.0215 L = 3.58 M HCl 6. What is the equivalent weight of Ca(OH)2? a. 24.7 g/eq b. 74.1 g/eq 74.1 g Ca(OH)2 1 mole c. 148.2 g/eq 1 mole 2 eq = 37 g/eq 7. How many equivalents are in 1 mole of H3PO4? a. 0.33 b. 1 c. 3 1 mole H3PO4 d. 37 g/eq d. 98 3 eq 1 mole e. 33 = 3 eq 8. How many equivalents are in 1.00 gram of H2SO4? (MM = 98 g/mol) a. 0.020 b. 0.010 c. 0.0051 1.00 g H2SO4 1 mole 98 g 9. What is the normality of 12.0 M H2SO4? a. 3.0 N b. 6.0 N 2 eq 1 mole 10. What is the molarity of 1.0 N HI? a. 7.8 x 10-3 b. 128 c. 1.0 N = #eq X M M= N/eq e. 49 = 0.020 eq c. 12.0 N N = 2 X 12.0 M N = #eq X M d. 98 d. 4.0 N e. 24.0 N N = 24.0 N d. 2.0 M= 1.0N/1eq M = 1.0M 11. Suppose 9.8 grams of H2SO4 (MW = 98 g/mol) are dissolved in 250.0 mL of aqueous solution. What is the Normality of H2SO4 in the solution? a. 19.6 N b. 0.40 N c. 0.20 N d. 4.9 N e. 0.80 N 9.8 g H2SO4 1 mole H2SO4 98 g H2SO4 = 0.10 mole H2SO4 0.250 L = 0.40 M x 2 eq = 0.80 N H2SO4 12. What volume of 3.0 N H3PO4 would exactly neutralize 250.0 mL of aqueous 2.0 N NaOH? a. 375 mL b. 166.7 mL c. 250.0 mL d. 45 mL H3PO4 + 3 NaOH 3 HOH + Na3PO4 H3PO4 = 3.0 N/ 3 eq= 1.0 M 250.0 mL 1L 2.0 mole NaOH 1000 mL 1L 1 mole H3PO4 3 mole NaOH 1L 1000 mL 1.0 mole H3PO4 1L 13. What is the hydronium ion concentration in a solution which is 0.10 M HNO3(aq)? a. 0.30 M c. 6.7 x 10-3 M e. 2.1 x 10-2 M -7 b. 0.10 M d. 1.0 x 10 M 0.10 mole HNO3 1L 1 mole H3O+ 1 mole HNO3 = 0.10 M H3O+ = 166.7 mL H3PO4 14. What is the hydroxide ion concentration in 1.0 M HBr? a. 1.0 M b. 1.0 x 10-13 M c. 1.0 x 10-14 M Kw= [H3O+][OH-] [OH-] = 1.0x10-14 / 1.0 1.0x 10-14 15. What is the pH of 1.0 x 10-3 M aqueous HClO4? a. 10-7 b. -3.0 c. 0.0 pH = -log [H3O+] d. 1.0 x 10-7 M d. 3.0 e. 1.0 pH = -log[1.0x10-3] pH = 3.0 16. What is the hydronium ion concentration in a solution which has [OH-1] = 1.0 x 10- 2 M? a. 1.0 x 10-12 M c. 1.0 x 10-16 M e. 1.0 x 10-7 M -2 b. 1.0 x 10 M d. 12 Kw= [H3O+][OH-] [H3O+]= 1.0x10-14 / 1.0x10-2 1.0x10-12 17. Identify the INCORRECT statement: a. As the pH increases the hydroxide ion decreases. b. As the pH increases the hydronium ion concentration decreases. c. As the pH increases the Kw of water remains the same. d. As the pH increases the product [H3O+][OH-] remains constant. e. As the pH increases the solution becomes less acidic and more alkaline. 18. Write the conjugate base for each of the following: a. H2S HSc. NH3 -1 b. HS S-2 d. H2SO3 NH2HSO3- 19. Which acid is the weakest acid? Refer to the table 6 on p 485 of your textbook. a. H2S c. HC2H3O2 e. HF b. HNO3 d. HClO 20. What is the Ka of HNO2(aq)? Refer to the table of acids given. a. -0.525 c. 0.525 e. 1.8 x 10-5 b. 3.35 d. 4.5 x 10-4 21. What is the pH of a 0.10 M solution of HF in water? The Ka = 7.2 x 10- 4. a. -2.07 c. 0.10 e. 2.1 b. 8.5 x 10-3 d. 3.14 HF + H2O H3O+ + F0.10 M 0 0 0.10-x x x K= [P]/[R] 7.2x10-4 = x2/0.10 x = 0.0085 M pH = -log[0.0085] pH= 2.1 22. What is the percent ionization of the acid in Problem #21? a. 100% c. 0.11% b. 8.5% d. 0.0011% e. 0.08% 7.2x10-4/0.0085 = 0.085 x 100% = 8.5% 23. What is the pH of a 0.20 M aqueous solution of the base methylamine, CH3NH2? Kb = 5.0 x 10-4. a. 2.0 b. 12.0 c. 16.0 d. 10.0 e. 0.01 CH3NH2 + H2O CH3NH3+ + OH0.20 M 0 0 0.20 – x x x K= [P]/[R] 5.0x10-4 = x2/0.20 x = 0.010 M pH = -log[0.010] pOH = 2.00 pH + pOH = 14 pH = 14 – 2 = 12.00 24. Using your knowledge of the Brønsted-Lowry theory of acids and bases, write equations for the following acid-base reactions and indicate each conjugate acid-base pair: a. HNO3 + (OH)-1 HOH(l) + NO-(aq) A B CA CB b. CH3NH2 + H2O HCH3NH2-(aq) + OH-(aq) B A CA CB c. (OH)-1 + HPO4-2 HOH(l) + PO4-3(aq) B A CA CB 25. The compound NaOH is a base by both of the theories we discussed in class. However, both of the theories describe what a base is in different terms. Use your knowledge of these theories to describe NaOH as an Arrhenius base and a Brønsted-Lowry base. NaOH is an Arrhenius base because it produces an (OH)-1 ion when dissolved in solution. NaOH is a Brønsted-Lowry base because it is a proton acceptor. The (OH)-1 portion of the NaOH reacts to remove a hydrogen ion from another compound. 26. When hydrogen chloride reacts with ammonia, ammonium chloride is formed. Write the equation for this process, and indicate which of the reagents is the acid and which is the base. HCl(aq) + NH3(aq) (NH4)Cl(aq) NH3 is a Lewis base because it uses its lone pair electrons to pull a hydrogen atom from hydrochloric acid. HCl is a Lewis acid because it accepts electrons from NH3 when the H is transferred. 27. Write an equation for the reaction each of the following reactions and indicate what each reaction produces: a. Carbon dioxide and water CO2(g) + H2O() H2CO3(aq) b. Sodium oxide and water Na2O(s) + H2O() 2 NaOH(aq) c. Dichlorine trioxide and water Cl2O3(g) + H2O() 2 HClO2(aq) d. Beryllium oxide and water BeO(s) + H2O() Be(OH)2(aq) 28. Write the names for the following acids and bases: a. b. c. d. e. KOH _____potassium hydroxide_____________________ H2S ______hydrosulfuric acid_______________________ HC2H3O2 ____acetic acid___________________________ Fe(OH)2 _____iron (II) hydroxide_____________________ HCN _____hydrocyanic acid________________________ 29. Calculate the pH, pOH and [OH-1] of a solution in which the [H+1] = 1.2 x 10-3. Calculate each significantly! pH = -log [H+] pH = -log[1.2x10-3] pH = 2.92 pH + pOH = 14 pOH = 14 – 2.92 = 11.08 pOH kw = ka x kb kb = 1.0x10-14 / 1.2x10*3 kb = [OH-] = 8.33x10-12 or: [OH-] = 10-11.08 = 8.33x10-12 M 30. Calculate the pH, pOH, and [H+1] of a solution in which the [OH-1] = 2.34 x 10-5. Calculate each significantly! pOH = -log[2.34 x 10-5] pOH = 4.631 pH = 14 - 4.631 pH = 9.369 kw = ka x kb ka = 1.0x10-14 / 2.34 x 10-5 ka = [H+] = 4.27x10-10 or: [H+] = 10-9.369 = 4.27x10-10 M 31. What is the pH and pOH of a solution that was made by adding 400 mL of water to 350 mL of 5.0 x 10-3 M NaOH solution? NaOH Na+ + OH(5.0x10 M)(0.350L) = 0.0017 mole NaOH 0.0017 mole NaOH x 1 mole OH-/1 mole NaOH = 0.0017 mole OH0.0017 mole OH- / 0.750 L = 0.0023 M OHpOH = -log[0.0023] 2.63 pH = 14 – 2.63 = 11.37 -3 32. What is the pH and pOH of a solution with a volume of 5.4 L that contains 15 grams of hydrochloric acid and 25 grams of nitric acid? 15 g HCl 25 g HNO3 1 mole 36.46 g 1 mole 63.02 g = 0.41 mole HCl = 0.40 mole HNO3 0.41 + 0.40 = 0.81 mole total / 5.4 L = 0.15 M H+ pH = -log[0.15] pH = 0.82 pH + pOH = 14 14 - 0.82 pOH = 13.18 33. What is an electrolyte? Which of the following will produce stronger electrolyte solutions, strong acids and bases or weak acids and weak bases? If one was comparing two strong acids or two strong bases, how would they determine which solution would produce a stronger electrolyte solution? An electrolyte is a substance that produces a large number of ions when dissolved in solution. Strong acids and bases would be stronger electrolytes because they produce more ions in solution than weak acids and bases. To compare two strong acids or two strong bases, one would compare the Ka and Kb values to determine which would be a stronger electrolyte. The larger the K value the stronger the electrolyte. 34. Write the dissociation reactions for the polyprotic acid, Arsenic acid (H3AsO4). Using the following k values, label the k values for each reaction: (ka1 = 5 x 10-3, ka2 = 8 x 10-8, ka3 = 6 x 10-10) H3AsO4(aq) H2AsO4-1(aq) + H3O+1(aq) H2AsO4-1(aq) HAsO4-2(aq) + H3O+1(aq) HAsO4-2(aq) AsO4-3(aq) + H3O+1(aq) ka1 = 5 x 10-3 ka2 = 8 x 10-8 ka3 = 6 x 10-10 35. Using the following Ka values, place the following acids in order of increasing acid strength. HClO4 CH3OOH ka = 1 x 107 ka = 1.76 x 10-5 HCN < CH3OOH < HF < HClO4 HCN HF Ka = 4.93 x 10-10 Ka = 3.53 x 10-4 36. Using the Ka values from above, calculate the Kb values and place the following bases in order of increasing strength. (Kw = Ka x Kb) Kb = Kw/Ka CN-1, F-1, CH3OO-1, ClO4-1 CN- : kb = 1.0x10-14 /4.93x10-10 kb = 2.0x10-5 F- : kb = 1.0x10-14 / 3.53x10.4 Kb = 2.8x10.11 CH3OO- : kb = 1.0x10-14 / 1.76x10-5 kb = 5.7x10=10 ClO4- : kb = 1.0x10-14 / 1x107 kb = 1x10-21 ClO4-1 <F-1 < CH3OO-1 < CN-1 37. Draw titration curves for the following titrations and label the x-axis, y-axis, and equivalence point: a. 0.100 M NaOH is titrated into a solution of 0.200 M HNO3. b. 1.0 M HCl is titrated into a solution of 0.50 M NaOH. 38. Indicate whether the following salts will produce an acidic, basic, or neutral solution when dissolved in water. a. NaNO3 SB-SA WCA-WCB neutral b. NH4ClO4 WB-SA SCA-WCB acidic c. NaCO3 SB-WA WCA-SCB basic 39. Which of the following acids have relatively weak conjugate bases? a. HF b. HCl c. H2SO4 d. HC2H3O2 40. Which of the following will have relatively strong conjugate acids? a. SO4-2 b. Br-1 c. CN-1 d. C2H3O2-1