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American Chemical Society General Chemistry Solutions and Reactions

Concentration, net ionic equations, solubility, and oxidation numbers.

These questions are original. This is not an official American Chemical Society exam, and FreeExam is not affiliated with the American Chemical Society.

  1. 1.A volumetric flask contains 0.250 L of solution and 0.500 mol of dissolved sodium chloride. What is the molarity of NaCl?

  2. 2.A student dissolves 0.200 mol of glucose and adds water until the solution volume is 0.500 L. What is the molarity of glucose?

  3. 3.A storage carboy holds 4.00 L of potassium nitrate solution that contains 2.00 mol of KNO3. What is the molarity?

  4. 4.A chemist dissolves 0.0800 mol of HCl and dilutes the solution to 250 mL. What is the molarity of HCl?

  5. 5.A prep beaker contains 0.125 mol of NaOH dissolved to a total volume of 500 mL. What is the molarity of NaOH?

  6. 6.An ammonia stock solution contains 1.50 mol of NH3 in 3.00 L of solution. What is the molarity of NH3?

  7. 7.Blue copper(II) sulfate, 0.0400 mol, is dissolved and brought to a final volume of 200 mL. What is the molarity of CuSO4?

  8. 8.A vinegar sample contains 0.200 mol of acetic acid in 0.800 L of solution. What is the molarity of acetic acid?

  9. 9.A student pipets a potassium bromide solution: 0.0200 mol of KBr is present in 80.0 mL. What is the molarity of KBr?

  10. 10.A technician takes 25.0 mL of 2.00 M HCl and adds water until the volume is 100.0 mL. What is the molarity of the diluted acid?

  11. 11.How many milliliters of 6.00 M NaOH are needed to prepare 300 mL of 0.200 M NaOH?

  12. 12.A lab dilutes 40.0 mL of 0.500 M copper(II) sulfate to a final volume of 200 mL. What is the molarity of CuSO4 after dilution?

  13. 13.What volume of 2.00 M acetic acid, in mL, must be diluted to 250 mL to produce a 0.400 M solution?

  14. 14.Diluting 15.0 mL of a potassium nitrate stock to 120 mL produces a 0.800 M solution. What was the molarity of the stock?

  15. 15.Water is added to 50.0 mL of 3.00 M sulfuric acid until the volume reaches 750 mL. What is the molarity of the diluted H2SO4?

  16. 16.How many milliliters of 10.0 M HCl are required to prepare 500 mL of 0.500 M HCl?

  17. 17.A student dilutes 80.0 mL of 0.250 M NaCl to a final volume of 2.00 L. What is the molarity of the diluted solution?

  18. 18.How many milliliters of water must be added to 30.0 mL of 4.00 M ammonia to make the concentration 1.00 M? Assume the volumes add.

  19. 19.A brine is prepared from 15.0 g of sodium chloride and 85.0 g of water. What is the mass percent of NaCl?

  20. 20.A camping-stove fuel blend contains 8.00 g of ethanol and 32.0 g of water. What is the mass percent of ethanol?

  21. 21.A mixture contains 18.0 g of water (molar mass 18.0 g/mol) and 46.0 g of ethanol (molar mass 46.0 g/mol). What is the mole fraction of water?

  22. 22.A syrup is made from 25.0 g of table sugar and 75.0 g of water. What is the mass percent of sugar?

  23. 23.A solution contains 58.5 g of NaCl (molar mass 58.5 g/mol) and 180 g of water (molar mass 18.0 g/mol). What is the mole fraction of NaCl?

  24. 24.A pickling liquid contains 12.0 g of sodium chloride dissolved in 188 g of water. What is the mass percent of NaCl?

  25. 25.A radiator mix contains 40.0 g of ethylene glycol and 60.0 g of water. What is the mass percent of ethylene glycol?

  26. 26.A solvent pair is 32.0 g of methanol (molar mass 32.0 g/mol) plus 18.0 g of water (molar mass 18.0 g/mol). What is the mole fraction of methanol?

  27. 27.A lab standard is prepared from 5.00 g of potassium chloride and 45.0 g of water. What is the mass percent of KCl?

  28. 28.Aqueous silver nitrate is poured into aqueous sodium chloride. Which product is the solid?

  29. 29.Aqueous barium chloride is mixed with aqueous potassium sulfate. Which product is the solid?

  30. 30.Aqueous lead(II) nitrate is combined with aqueous sodium chloride. Which product is the solid?

  31. 31.Aqueous calcium nitrate is mixed with aqueous sodium sulfate. Which product is the solid?

  32. 32.Aqueous magnesium chloride is mixed with aqueous sodium hydroxide. Which product is the solid?

  33. 33.Aqueous iron(III) nitrate is added to aqueous potassium hydroxide. Which product is the solid?

  34. 34.Aqueous mercury(I) nitrate is mixed with aqueous potassium chloride. Which product is the solid?

  35. 35.Aqueous copper(II) sulfate is mixed with aqueous sodium hydroxide. Which product is the solid?

  36. 36.Aqueous sodium nitrate is mixed with aqueous potassium chloride. Which product, if any, is a solid?

  37. 37.Aqueous silver nitrate and aqueous sodium chloride form solid silver chloride. Which ions are spectators?

  38. 38.Aqueous barium nitrate and aqueous sodium sulfate form solid barium sulfate. Which statement is the net ionic change, in words?

  39. 39.Aqueous lead(II) nitrate and aqueous potassium chloride form solid lead(II) chloride. Which ions remain unchanged as spectators?

  40. 40.Aqueous magnesium chloride and aqueous potassium hydroxide form solid magnesium hydroxide. What is the net ionic change, in words?

  41. 41.Aqueous iron(III) nitrate and aqueous sodium hydroxide form solid iron(III) hydroxide. Which ions are spectators?

  42. 42.Aqueous calcium chloride and aqueous sodium sulfate form solid calcium sulfate. What is the net ionic change, in words?

  43. 43.Aqueous mercury(I) nitrate and aqueous sodium chloride form solid mercury(I) chloride. Which ions are spectators?

  44. 44.Aqueous copper(II) chloride and aqueous potassium hydroxide form solid copper(II) hydroxide. What is the net ionic change, in words?

  45. 45.Aqueous sodium chloride is mixed with aqueous potassium nitrate, and no solid appears. Which description of the ions is correct?

  46. 46.Hydrochloric acid and sodium hydroxide react 1 mol to 1 mol. How many moles of NaOH neutralize 0.250 mol of HCl?

  47. 47.Sulfuric acid has two acidic hydrogens. How many moles of NaOH completely neutralize 0.150 mol of H2SO4?

  48. 48.Phosphoric acid has three acidic hydrogens. How many moles of KOH completely neutralize 0.0900 mol of H3PO4?

  49. 49.Calcium hydroxide supplies two hydroxide ions per formula unit. How many moles of Ca(OH)2 neutralize 0.400 mol of HCl?

  50. 50.Nitric acid and sodium hydroxide react 1 mol to 1 mol. How many moles of NaOH neutralize 0.0600 mol of HNO3?

  51. 51.Barium hydroxide supplies two hydroxide ions per formula unit. How many moles of Ba(OH)2 neutralize 0.500 mol of HCl?

  52. 52.Both acidic hydrogens of sulfuric acid react. How many moles of NaOH completely neutralize 0.220 mol of H2SO4?

  53. 53.Acetic acid, CH3COOH, has one acidic hydrogen. How many moles of KOH neutralize 0.0350 mol of acetic acid?

  54. 54.Sulfuric acid has two acidic hydrogens, and calcium hydroxide has two hydroxide ions. How many moles of Ca(OH)2 completely neutralize 0.180 mol of H2SO4?

  55. 55.In H2SO4, hydrogen is +1, oxygen is -2, and the oxidation numbers of a neutral compound sum to 0. What is the oxidation number of sulfur?

  56. 56.In KMnO4, potassium is +1, each oxygen is -2, and the neutral compound sums to 0. What is the oxidation number of manganese?

  57. 57.The oxidation number of an element in its elemental form is 0. What is the oxidation number of each oxygen atom in O2?

  58. 58.In water, each hydrogen is +1 and the neutral molecule sums to 0. What is the oxidation number of oxygen in H2O?

  59. 59.In the sulfate ion, SO4 2-, each oxygen is -2 and the oxidation numbers sum to the ion charge, -2. What is the oxidation number of sulfur?

  60. 60.In compounds, an alkali metal has oxidation number +1. What is the oxidation number of sodium in NaCl?

  61. 61.In hydrogen peroxide, H2O2, each hydrogen is +1 and the neutral molecule sums to 0. What is the oxidation number of each oxygen?

  62. 62.In K2Cr2O7, each potassium is +1, each oxygen is -2, and the neutral compound sums to 0. What is the oxidation number of each chromium?

  63. 63.In HNO3, hydrogen is +1, each oxygen is -2, and the neutral compound sums to 0. What is the oxidation number of nitrogen?

  64. 64.Zinc metal reacts with copper(II) ion to form zinc ion and copper metal. Which species is oxidized, and which is reduced?

  65. 65.Magnesium metal becomes magnesium ion while hydrogen ion becomes hydrogen gas. Which species is the oxidizing agent?

  66. 66.Iron metal reacts with silver ion to form iron(II) ion and silver metal. Which species is oxidized?

  67. 67.Copper metal reacts with silver ion to form copper(II) ion and silver metal. Which species is the oxidizing agent?

  68. 68.Sodium metal reacts with chlorine gas to form sodium chloride. Which species is reduced?

  69. 69.Hydrogen gas and oxygen gas react to form water. Which species is oxidized?

  70. 70.Tin(II) ion reacts with iron(III) ion to form tin(IV) ion and iron(II) ion. Which species is the oxidizing agent?

  71. 71.Aluminum metal reacts with iron(III) ion to form aluminum ion and iron(II) ion. Which pairing is correct?

  72. 72.Bromine reacts with iodide ion to form bromide ion and iodine. Which species is the oxidizing agent?

  73. 73.The unbalanced skeleton, in words, is aluminum metal plus oxygen gas producing aluminum oxide, Al2O3. Which coefficients balance it, in the order aluminum, oxygen, aluminum oxide?

  74. 74.The unbalanced skeleton is hydrogen gas plus oxygen gas producing water. Which coefficients balance it, in the order hydrogen, oxygen, water?

  75. 75.The unbalanced skeleton is iron metal plus oxygen gas producing iron(III) oxide, Fe2O3. Which coefficients balance it, in the order iron, oxygen, iron(III) oxide?

  76. 76.The unbalanced skeleton is phosphorus plus chlorine gas producing phosphorus trichloride, PCl3. Which coefficients balance it, in the order phosphorus, chlorine, phosphorus trichloride?

  77. 77.The unbalanced skeleton is sodium metal plus chlorine gas producing sodium chloride. Which coefficients balance it, in the order sodium, chlorine, sodium chloride?

  78. 78.The unbalanced skeleton is magnesium metal plus nitrogen gas producing magnesium nitride, Mg3N2. Which coefficients balance it, in the order magnesium, nitrogen, magnesium nitride?

  79. 79.The unbalanced skeleton is hydrogen gas plus chlorine gas producing hydrogen chloride. Which coefficients balance it, in the order hydrogen, chlorine, hydrogen chloride?

  80. 80.The unbalanced skeleton is aluminum metal plus hydrochloric acid producing aluminum chloride and hydrogen gas. Which coefficients balance it, in the order aluminum, HCl, aluminum chloride, hydrogen?

  81. 81.The unbalanced skeleton is zinc metal plus hydrochloric acid producing zinc chloride and hydrogen gas. Which coefficients balance it, in the order zinc, HCl, zinc chloride, hydrogen?

  82. 82.A 1 m sugar solution and a 1 m NaCl solution are made in the same solvent. Sugar does not dissociate, and NaCl gives about two particles per formula unit. Which solution has the lower freezing point?

  83. 83.Equal molal solutions of NaCl and of sugar are boiled. NaCl separates into ions, and sugar stays as molecules. Which solution has the higher boiling point?

  84. 84.What are the ideal van 't Hoff factors for NaCl and for sugar, a nonelectrolyte?

  85. 85.One beaker holds 0.50 m glucose, a nonelectrolyte. Another holds 0.50 m NaCl. Which solution freezes at the lower temperature?

  86. 86.A sugar solution and an NaCl solution show the same freezing-point depression. Sugar has a van 't Hoff factor of 1, and ideal NaCl has a factor of about 2. How do the formula-unit molalities compare?

  87. 87.One mole of NaCl and one mole of sugar are dissolved in separate, equal masses of water. Which solute raises the boiling point more?

  88. 88.Seawater, which contains dissolved salts, freezes at a lower temperature than pure water. Why?

  89. 89.Compare ideal particle counts for a 1 m NaCl solution, van 't Hoff factor about 2, and a 2 m sugar solution, factor 1. Which has more dissolved particles per kilogram of solvent?

  90. 90.A 0.20 m sugar solution and a 0.20 m NaCl solution are heated. Which has the higher boiling point?

  91. 91.A solution already holds undissolved solute at the bottom. An extra crystal of that solute is added and does not shrink. What does the test show?

  92. 92.A clear potassium nitrate solution can still hold more solute. A small KNO3 crystal is dropped in. What happens to that crystal?

  93. 93.A saturated solution sits in contact with its own solid. Another crystal of the solute is added at the same temperature. What happens to the concentration of dissolved solute?

  94. 94.A student drops one crystal of the solute into a clear solution, and the crystal disappears completely. Before that crystal was added, the solution was

  95. 95.A clear sugar solution is tested with one sugar crystal. The crystal remains the same size for a long time at constant temperature. The original solution was

  96. 96.A cooled solution still looks clear but holds more dissolved solid than a saturated solution at that temperature. One crystal is added, and a large amount of solid appears. Before the crystal, the solution was

  97. 97.Which observation fits an unsaturated solution when a small crystal of the same solute is added at constant temperature?

  98. 98.In beaker A, an added crystal of the solute dissolves. In beaker B, an added crystal does not dissolve and the concentration does not change. Which pairing is correct?

  99. 99.A saturated solution is warmed until every bit of undissolved solid disappears. A fresh crystal of the solute then dissolves as well. The warm solution is

  100. 100.Sodium chloride is dissolved in water and the ions separate completely. A conductivity bulb glows brightly. How is this solution classified?

  101. 101.Acetic acid, CH3COOH, is stirred into water. Only a small fraction of the molecules form ions, and the solution conducts poorly. What is acetic acid in water?

  102. 102.Sucrose dissolves in water as whole molecules. The solution does not conduct electricity. How is aqueous sucrose classified?

  103. 103.Hydrochloric acid is added to water and ionizes completely into hydrogen ion and chloride ion. The solution conducts strongly. What is aqueous HCl?

  104. 104.Aqueous ammonia reacts with water only to a small extent, so only a small fraction of NH3 is converted to ions. How is this solution classified?

  105. 105.Ethanol is mixed with water and remains as molecules. The mixture does not light a conductivity bulb. What is ethanol in water?

  106. 106.Sodium hydroxide dissolves in water and separates completely into sodium ions and hydroxide ions. How is aqueous NaOH classified?

  107. 107.Hydrofluoric acid, HF, is dissolved in water and only part of it ionizes. The solution conducts, but much less than the same concentration of HCl. What is aqueous HF?

  108. 108.Glucose is dissolved in water for an intravenous solution. The molecules stay intact, and the solution does not conduct. How is aqueous glucose classified?