Chapter 4: Chemical Composition 1) A 5.05 g sample of qua

Homework answers / question archive / Chapter 4: Chemical Composition 1) A 5

Chapter 4: Chemical Composition 1) A 5

Chemistry

Share With

Chapter 4: Chemical Composition

1) A 5.05 g sample of quartz (SiO₂) contains 2.36 g of silicon. What are the percents of silicon and oxygen in quartz?

A) 53.3% Si and 46.7% O

B) 46.7% Si and 53.3% O

C) 29.9% Si and 70.1% O

D) 70.1% Si and 29.9% O

E) 46.7% Si, and insufficient information to calculate % O

2. A 6.25 g sample of magnetite (Fe₃O₄) contains 4.52 g of Fe. What are the percents of iron and oxygen in magnetite?

A) 28.6% Fe and 71.4% O D) 27.7% Fe and 72.3% O

B) 42.8% Fe and 57.2% O E) 57.2% Fe and 42.8% O

C) 72.3% Fe and 27.7% O

3. A 7.50 g sample of pyrite (FeS₂) contains 3.49 g of iron. What are the percents of iron and sulfur in pyrite (also known as “Fool's Gold” because of its golden color)?

A) 57.4% Fe and 42.6% S D) 46.5% Fe and 53.5% S

B) 66.7% Fe and 33.3% S E) 53.5% Fe and 46.5% S

C) 33.3% Fe and 66.7% S

4. Malachite is a green colored mineral that is 57.5% copper. What mass of copper is present in a 250.0 g sample of malachite?

A) 63.6 g B) 127 g C) 435 g D) 36.5 g E) 144 g

5. Barium sulfate is a compound used to assist in diagnosing medical problems through x-ray analysis and is 58.8% barium. What mass of barium is present in a 620 mg tablet of barium sulfate?

A) 81 mg B) 230 mg C) 360 mg D) 1100 mg E) 11 mg

6. Which of the following statements is incorrect?

A) PH₃ has 3 times as many hydrogen atoms as phosphorus atoms.

B) MgO has an equal number of magnesium ions and oxygen ions.

C) BaBr₂ has half as many barium ions as bromide ions.

D) N₂O₅ has 2.5 times as many nitrogen atoms as oxygen atoms.

E) SF₄ has 4 times as many fluorine atoms as sulfur atoms.

7. Which of the following statements is incorrect?

A) CH₄ has ¼ as many carbon atoms as hydrogen atoms.

B) H₂O has twice as many oxygen atoms as hydrogen atoms.

C) SO₃ has three times as many oxygen atoms as sulfur atoms.

D) P₄O₁₀ has 2.5 times as many oxygen atoms as phosphorus atoms.

E) SrF₂ has twice as many fluoride ions as strontium ions.

8. Which of the following statements is incorrect?

A) N₂H₄ has four times as many hydrogen atoms as nitrogen atoms.

B) SF₄ has ¼ as many sulfur atoms as fluorine atoms.

C) SO₂ has twice as many oxygen atoms as sulfur atoms.

D) Ca(NO₃)₂ has six times as many oxygen atoms as calcium ions.

E) H₂SO₄ has twice as many oxygen atoms as hydrogen atoms.

9. Which of the following statements is incorrect?

A) H₂SO₃ has 1.5 times as many oxygen atoms as hydrogen atoms.

B) Fe₂(SO₄)₃ has six times as many oxygen atoms as iron ions.

C) N₂H₄has twice as many hydrogen atoms as nitrogen atoms.

D) MgF₂ has half as many fluoride ions as magnesium ions.

E) Carbon dioxide has twice as many oxygen atoms as carbon atoms.

10. Which of the following sets of formulas is correct for the molecules in the figure?

A) H₂SO₃, SCl₄, C₂H₄ D) H₂SO₄, SCl₄, CH₄

B) H₂SO₃, SCl₃, C₂H₄ E) H₂SO₄, SCl₄, C₂H₄

C) H₂SO₄, SCl₃, C₂H₄

11. Which of the following sets of formulas is correct for the molecules in the figure?

A) H₂SO₃, SCl₅, C₂H₅ D) H₂SO₄, SCl₆, CH₆

B) H₂SO₄, SCl₅, C₂H₅ E) H₂SO₃, SCl₆, C₂H₆

C) H₂SO₄, SCl₆, C₂H₆

12. How many formula units are in 0.25 mole of Na₂O?

A) 4.5 ´ 10²³ B) 0.75 C) 1.5 ´ 10²³ D) 4.2 ´ 10^–25 E) 0.25

13. How many formula units are in 2.0 moles of Fe(NO₃)₂?

A) 1.2 ´ 10²⁴ B) 3.6 ´ 10²⁴ C) 1.1 ´ 10²⁵ D) 2.0 E) 18

14. How many formula units are there in 2.5 moles of MgCl₂?

A) 2.5 B) 7.5 C) 1.5 ´ 10²⁴ D) 4.5 ´ 10²⁴ E) 4.2 ´ 10^–24

15. How many chloride ions are present in 0.100 mol of MgCl₂?

A) 0.200 Cl^– ions D) 3.32 ´ 10^–25 Cl^– ions

B) 6.02 ´ 10²² Cl^– ions E) 3.01 ´ 10²⁴ Cl^– ions

C) 1.20 ´ 10²³ Cl^– ions

16. How many nitrate ions are present in 0.200 mol of Zn(NO₃)₂?

A) 1.20 ´ 10²³ NO₃^– ions D) 6.64 ´ 10^–25 NO₃^– ions

B) 2.41 ´ 10²³ NO₃^– ions E) 0.400 NO₃^– ions

C) 3.01 ´ 10²⁴ NO₃^– ions

17. How many molecules of CO₂ are present in 0.100 mol of CO₂?

A) 6.02 ´ 10²² molecules D) 6.02 ´ 10²⁴ molecules

B) 4.40 molecules E) 0.100 molecules

C) 1.66 ´ 10^–25 molecules

18. How many molecules of HCl are present in 0.250 mol of HCl?

A) 4.15 ´ 10^–25 molecules D) 9.11 molecules

B) 1.51 ´ 10²³ molecules E) 0.250 molecules

C) 2.41 ´ 10²⁴ molecules

19. How many carbon atoms are there in 0.50 mole of CO₂?

A) 0.50 B) 1.50 C) 3.0 ´ 10²³ D) 9.0 ´ 10²³ E) 8.3 ´ 10²⁵

20. How many oxygen atoms are there in 0.25 mole of CO₂?

A) 0.50 B) 0.25 C) 3.0 ´ 10²³ D) 1.5 ´ 10²³ E) 4.2 ´ 10^–25

21. How many hydrogen atoms are there in 2.0 moles of CH₄?

A) 8.0 B) 2.0 C) 1.2 ´ 10²⁴ D) 1.3 ´ 10^–23 E) 4.8 ´ 10²⁴

22. How many oxygen atoms are present in 1.50 mol of Zn(NO₃)₂?

A) 4.50 atoms D) 5.42 ´ 10²⁴ atoms

B) 9.00 atoms E) 1.49 ´ 10^–23 atoms

C) 9.03 ´ 10²³ atoms

23. How many nitrogen atoms are present in 0.150 mol of Zn(NO₃)₂?

A) 9.03 ´ 10²² atoms D) 0.300 atoms

B) 1.81 ´ 10²³ atoms E) 0.450 atoms

C) 4.98 ´ 10^–25 atoms

24. Rank the substances in the figure from least atoms per mole to most atoms per mole.

A) SO₃< H₂SO₄< NaCl < Na D) NaCl < Na < SO₃< H₂SO₄

B) Na < NaCl < SO₃< H₂SO₄ E) H₂SO₄< SO₃< NaCl < Na

C) Na < NaCl < H₂SO₄< SO₃

25. Rank the substances in the figure from least atoms per mole to most atoms per mole.

A) SiO₂< C₂H₆< CO₂< Fe D) Fe < CO₂< SiO₂< C₂H₆

B) C₂H₆< SiO₂= CO₂< Fe E) C₂H₆< SiO₂< CO₂< Fe

C) Fe < CO₂= SiO₂< C₂H₆

26. Calculate the molar mass of HCl.

A) 36.46 g/mol D) 6.054 ´ 10^–23 g/mol

B) 13.02 g/mol E) 72.92 g/mol

C) 2.196 ´ 10²⁵ g/mol

27. Calculate the molar mass of PH₃.

A) 40.11 g/mol D) 93.92 g/mol

B) 31.98 g/mol E) 2.05 ´ 10²⁵ g/mol

C) 33.99 g/mol

28. Calculate the molar mass of Na₂SO₄.

A) 94.05 g/mol D) 142.05 g/mol

B) 71.06 g/mol E) 110.05 g/mol

C) 119.06 g/mol

29. Calculate the molar mass of CuSO₄·5H₂O.

A) 159.62 g/mol D) 185.72 g/mol

B) 249.70 g/mol E) 446.48 g/mol

C) 177.64 g/mol

30. Calculate the molar mass of Fe₃(PO₄)₂.

A) 237.64 g/mol D) 357.49 g/mol

B) 262.52 g/mol E) 525.04 g/mol

C) 245.79 g/mol

31. Calculate the molar mass of C₃H₆Cl₂.

A) 155.08 g/mol D) 72.49 g/mol

B) 77.54 g/mol E) 112.98 g/mol

C) 48.47 g/mol

32. The formula for novocaine, a local anesthetic, is C₁₃H₂₁N₂O₂. What is the molar mass of this compound?

A) 43.03 g/mol D) 38.00 g/mol

B) 237.32 g/mol E) 4.214 ´ 10^–5 g/mol

C) 2035.27 g/mol

33. Calcium phosphate, Ca₃(PO₄)₂, is used to treat calcium deficiencies. What is the molar mass of this compound?

A) 87.05 g/mol D) 230.02 g/mol

B) 167.05 g/mol E) 310.18 g/mol

C) 279.21 g/mol

34. Which of the following statements regarding atoms, molecules, and moles is correct?

A) Chemists are inherently lazy, so they weigh substances in order to avoid counting out the atoms or molecules in a sample.

B) It would be possible for an individual to count out a mole of atoms or molecules if they had a few days to do it.

C) A single grain of sand has about as many formula units of SiO₂ as there are sand grains on all of the beaches on Earth.

D) A mole of HCl would have the same mass as a mole of NaCl, since they have the same number of particles.

E) Since a mole of LiCl has a mass of 42.39 g, the average mass of a LiCl formula unit would be 42.39 mole.

35. Rank the following in order of increasing mass: 1.0 mole of methane (CH₄), 0.50 mole of water (H₂O), 0.20 mole of Fe, and 0.010 mole of U.

A) U < Fe < H₂O < CH₄ D) U < H₂O < CH₄< Fe

B) H₂O < CH₄< Fe < U E) U < H₂O < Fe < CH₄

C) H₂O < CH₄< U < Fe

36. Rank the following in order of increasing mass: 1.0 mole of SF₄, 0.50 mole of H₂S, 0.20 mole of Cu, and 0.10 mole of Pb.

A) Pb < Cu < H₂S < SF₄ D) Cu < H₂S < SF₄< Pb

B) Cu < H₂S < Pb < SF₄ E) SF₄< H₂S < Cu < Pb

C) Pb < Cu < SF₄< H₂S

37. Rank the following in order of increasing mass: 2.0 mole of SO₂, 1.0 mole of SO₃, 0.50 mole of Mo, and 0.25 mole of Rn.

A) SO₃< SO₂< Rn < Mo D) Mo < Rn < SO₂< SO₃

B) SO₂< SO₃< Mo < Rn E) Rn < Mo < SO₃< SO₂

C) Mo < Rn < SO₃< SO₂

38. If 4.05 ´ 10²³ molecules of a substance have a mass of 86.2 g, what is the molar mass of the substance?

A) 128 g/mol D) 4.70 ´ 10²¹ g/mol

B) 3.49 ´ 10²⁵ g/mol E) 58.0 g/mol

C) 2.13 ´ 10²² g/mol

39. If 8.53 ´ 10²⁴ molecules of a substance have a mass of 483 g, what is the molar mass of the substance?

A) 6.86 ´ 10³ g/mol D) 1.77 ´ 10²² g/mol

B) 34.1 g/mol E) 0.0293 g/mol

C) 4.12 ´ 10²⁷ g/mol

40. If 7.50 ´ 10²⁴ molecules of a substance have a mass of 454 g, what is the molar mass of the substance?

A) 2.73 ´ 10²⁶ g/mol D) 36.5 g/mol

B) 3.41 ´ 10²⁷ g/mol E) 12.5 g/mol

C) 5.65 ´ 10³ g/mol

41. A 50.0 g sample of a compound contains 2.20 ´ 10²³ molecules. Which of the following could be this compound?

A) PH₃ B) NH₃ C) PCl₃ D) PCl₅ E) NF₃

42. A 100.0 g sample of a compound contains 1.37 ´ 10²⁴ molecules. Which of the following could be this compound?

A) CO₂ B) NH₃ C) CH₄ D) CCl₄ E) CF₄

43. If the molar mass of a substance is 34.1 g/mol, what is the mass of 3.01 ´ 10²⁴ molecules of the substance?

A) 17.1 g B) 6.82 g C) 8.83 ´ 10²² g D) 1.03 ´ 10²⁴ g E) 1.70 ´ 10² g

44. If the molar mass of a substance is 20.0 g/mol, what is the mass of 3.01 ´ 10²⁵ molecules of the substance?

A) 0.400 g B) 10.0 g C) 1.00 ´ 10³ g D) 6.02 ´ 10²⁶ g E) 1.20 ´ 10²⁵ g

45. If the molar mass of a substance is 20.0 g/mol, what is the mass of 4.01 ´ 10²³ molecules of the substance?

A) 30.0 g B) 13.3 g C) 8.02 ´ 10²⁴ g D) 1.20 ´ 10²⁵ g E) 3.00 g

46. If the molar mass of a substance is 44.01 g/mol, what is the mass of 1.05 ´ 10²⁴ molecules of the substance?

A) 76.7 g B) 1.74 g C) 4.62 ´ 10²⁵ g D) 4.19 ´ 10^–23 g E) 25.2 g

47. Calculate the number of moles of NaHCO₃ (sodium bicarbonate, or baking soda) in a 5.0 g sample of this substance.

A) 0.096 mole D) 3.6 ´ 10²² moles

B) 0.060 mole E) 2.8 ´ 10²³ mole

C) 420 moles

48. Calculate the number of moles of NaOH (sodium hydroxide, an ingredient in drain cleaners and oven cleaners) in a 10.0 g sample of this substance.

A) 1.51 ´ 10²³ moles D) 4.00 ´ 10² moles

B) 1.66 ´ 10²³ mole E) 0.250 mole

C) 0.208 mole

49. Calculate the number of moles of CaCO₃ (calcium carbonate, or limestone) in a 20.0 g sample of this substance.

A) 2.00 ´ 10³ moles D) 1.36 ´ 10³ moles

B) 0.200 mole E) 1.20 ´ 10³ moles

C) 0.294 mole

50. Calculate the moles of sucrose, C₁₂H₂₂O₁₁, in a 15.0-g sample of this substance.

A) 342 mol D) 4.38 ´ 10^–2 mol

B) 22.8 mol E) 0.517 mol

C) 5.13 ´ 10³ mol

51. Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Li, He, Mg, C

A) He < C < Li < Mg D) He < Li < C < Mg

B) C < Li < Mg < He E) Mg < C < Li < He

C) Li < C < Mg < He

52. Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Br, Fe, Pb, Hg

A) Br < Hg < Fe < Pb D) Br < Fe < Hg < Pb

B) Pb < Hg < Br < Fe E) Hg < Pb < Br < Fe

C) Fe < Br < Hg < Pb

53. Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Sn, Si, Se, S

A) Sn < Se < S < Si D) S < Si < Se < Sn

B) Si < S < Se < Sn E) Se < Sn < S < Si

C) Si < S < Sn < Se

54. A chemical reaction requires 6.00 moles of Fe(NO₃)₃. What mass of iron(III) nitrate is needed?

A) 24.3 g B) 875 g C) 40.3 g D) 1.45 ´ 10³ g E) 515 g

55. 3.00 moles of NaOH (sodium hydroxide) are needed to prepare a solution. What mass of sodium hydroxide is required?

A) 13.3 g B) 120. g C) 93 g D) 10.3 g E) 1.81 ´ 10²⁴ g

56. 5.06 moles of iron(II) phosphate, Fe₃(PO₄)₂, are produced in a reaction. What mass of iron(II) phosphate is produced?

A) 520. g B) 20.3 g C) 1.81 ´ 10³ g D) 3.05 ´ 10²⁴ g E) 70.7 g

57. A chemical reaction requires 3.50 moles of copper(II) nitrate, Cu(NO₃)₂. What mass of copper(II) nitrate is needed?

A) 327 g B) 93.6 g C) 188 g D) 656 g E) 53.6 g

58. A chemical reaction produces 7.25 moles of barium sulfate, BaSO₄. What mass of barium sulfate is produced?

A) 185 g B) 233 g C) 1.69 ´ 10³ g D) 31.1 g E) 3.11 ´ 10^–2 g

59. If you have 10.0 g of sodium chloride, NaCl, how many formula units are in the sodium chloride sample?

A) 2.84 ´ 10²⁵ B) 3.52 ´ 10²⁴ C) 6.02 ´ 10²⁴ D) 1.03 ´ 10²³ E) 0.171

60. How many molecules are in a sample of sucrose (sugar), C₁₂H₂₂O₁₁, that has a mass of 15.0 g?

A) 0.0438 B) 2.64 ´ 10²² C) 0.0824 D) 4.96 ´ 10²² E) 9.03 ´ 10²⁴

61. How many formula units are in a sample of rust, Fe₂O₃, that has a mass of 5.0 g?

A) 1.9 ´ 10²⁵ B) 0.031 C) 1.9 ´ 10²² D) 0.070 E) 4.2 ´ 10²²

62. How many molecules are in a sample of water, H₂O, that has a mass of 50.0 g?

A) 1.67 ´ 10²⁴ molecules D) 3.01 ´ 10²⁵ molecules

B) 5.42 ´ 10²⁶ molecules E) 8.30 ´ 10^–23 molecules

C) 2.16 ´ 10²³ molecules

63. How many formula units are in a sample of NaCl that has a mass of 175 g?

A) 2.01 ´ 10²³ formula units D) 1.05 ´ 10²⁶ formula units

B) 1.80 ´ 10²⁴ formula units E) 2.91 ´ 10^–22 formula units

C) 6.16 ´ 10²⁷ formula units

64. How many moles are in a sample of ethanol, CH₃CH₂OH, that has a volume of 100.0 mL? The molar mass and density of ethanol are 46.07 g/mol and 0.789 g/mL, respectively.

A) 78.9 mol B) 1.71 mol C) 36.3 mol D) 2.75 mol E) 0.504 mol

65. How many moles are in a sample of ethylene glycol (commonly found in antifreeze), HOCH₂CH₂OH, that has a volume of 250.0 mL? The molar mass and density of ethylene glycol are 62.07 g/mol and 1.11 g/mL, respectively.

A) 4.47 mol D) 1.40 ´ 10⁴ mol

B) 0.276 mol E) 1.72 ´ 10⁴ mol

C) 3.63 mol

66. How many oxygen atoms are in 75.0 g of SO₃?

A) 225 atoms D) 1.69 ´ 10²⁴ atoms

B) 0.937 atoms E) 4.52 ´ 10²⁵ atoms

C) 5.64 ´ 10²³ atoms

67. How many hydrogen atoms are in 135 g of H₂O?

A) 170 atoms D) 8.04 ´ 10²² atoms

B) 4.51 ´ 10²⁴ atoms E) 2.49 ´ 10^–23 atoms

C) 9.02 ´ 10²⁴ atoms

68. How many sodium ions are in 125 g of Na₂SO₄?

A) 1.06 ´ 10²⁴ atoms D) 1.37 ´ 10²⁴ atoms

B) 5.30 ´ 10²³ atoms E) 1.46 ´ 10^–24 atoms

C) 6.84 ´ 10²³ atoms

69. How many nitrate ions are in 75.0 g of Zn(NO₃)₂?

A) 0.396 atoms D) 4.77 ´ 10²³ atoms

B) 0.792 atoms E) 6.57 ´ 10^–25 atoms

C) 2.38 ´ 10²³ atoms

70. Rank the following compounds in order from least nitrogen atoms to most nitrogen atoms in a 50.0 g sample: N₂, N₂O₅, NH₃, NH₄Cl

A) N₂< N₂O₅< NH₃< NH₄Cl D) NH₃< NH₄Cl < N₂< N₂O₅

B) N₂O₅< NH₄Cl < NH₃< N₂ E) NH₄Cl < NH₃< N₂< N₂O₅

C) N₂< NH₃< NH₄Cl < N₂O₅

71. Rank the following compounds in order from least phosphorus atoms to most phosphorus atoms in a 50.0 g sample: P₄, P₄O₁₀, PH₃, PCl₃

A) PCl₃< P₄O₁₀< PH₃< P₄ D) P₄O₁₀< PCl₃< PH₃< P₄

B) PCl₃< P₄O₁₀< P₄< PH₃ E) P₄< P₄O₁₀< PCl₃< PH₃

C) P₄< PH₃< P₄O₁₀< PCl₃

72. Rank the following compounds in order from least chlorine atoms to most chlorine atoms in a 50.0 g sample: Cl₂, ClF₃, Cl₂O, PCl₃

A) ClF₃< Cl₂O < Cl₂< PCl₃ D) ClF₃< PCl₃< Cl₂< Cl₂O

B) PCl₃< Cl₂O < Cl₂< ClF₃ E) Cl₂O < Cl₂< ClF₃< PCl₃

C) ClF₃< PCl₃< Cl₂O < Cl₂

73. What is the mass of 3.5 ´ 10²³ molecules of CO₂?

A) 1.7 g B) 26 g C) 0.58 g D) 75 g E) 1.5 ´ 10²⁵g

74. What is the mass of 4.5 ´ 10²³ molecules of SO₂?

A) 2.9 ´ 10²⁵g B) 64 g C) 86 g D) 36 g E) 48 g

75. What is the mass of 2.4 ´ 10²³ molecules of NO₂?

A) 75 g B) 18 g C) 1.2 ´ 10² g D) 1.1 ´ 10²³ g E) 12 g

76. What is the mass of 7.4 ´ 10²⁴ molecules of SO₃?

A) 12 g B) 590 g C) 980 g D) 6.5 g E) 0.15 g

77. What is the mass of 1.2 ´ 10²⁴ molecules of F₂?

A) 0.052 g B) 9.5 g C) 19 g D) 38 g E) 76 g

78. Which of the following statements regarding empirical formulas, molecular formulas, and percent composition is correct?

A) The empirical formula and molecular formula of a given compound are always the same.

B) Two compounds having different percent compositions of the same two elements are not the same compound.

C) The empirical formula and molecular formula of a given compound are never the same.

D) Data on the percent composition of the elements in a given compound is insufficient to determine the empirical formula of the compound.

E) The compound S₂Cl₂ would have the same empirical and molecular formulas.

Ans: B

79. Which of the following statements regarding empirical formulas, molecular formulas, and percent composition is correct?

A) The compounds NO₂and N₂O₄ have the same empirical formula.

B) The compounds NO₂and N₂O₄ have the same molecular formula.

C) The empirical formula of H₂O₂ is H₂O.

D) The empirical formula of N₂O₅ is NO_2.5.

E) The compounds PCl₃ and PCl₅ would have the same percent composition.

80. Which of the following statements regarding empirical formulas, molecular formulas, and percent composition is correct?

A) A compound with the molecular formula P₄O₁₀would have the empirical formula P₄O₁₀.

B) It is not possible to determine the empirical formula of a compound if given only its percent composition.

C) If the molecular formula of a compound is C₆H₅Cl, its empirical formula is the same.

D) Empirical formulas contain more information than molecular formulas.

E) Formulas for ionic compounds are normally given as molecular formulas.

81. Which of the molecules in the figure have an empirical formula that is different from their molecular formula?

A) H₂O_2, N₂O_4,and HCO₂H D) all of the compounds

B) SiO₂ E) none of the compounds

C) H₂O₂ and N₂O₄

82. Which of the substances in the figure have the same empirical and molecular formulas?

A) S₂Cl₂ and C₆H₆ D) N₂O₃ and NaCl

B) none of the substances E) N₂O₃ only

C) all of the substances

83. Given the following molecular formulas, determine the empirical formula of each compound: N₂O₅, PCl₃, H₂O₂, C₆H₄Cl₂.

A) N₂O₅, PCl₃, HO, C₆H₄Cl₂ D) NO_2.5, PCl₃, HO, C₃H₂Cl

B) N₂O₅, PCl₃, H₂O, C₆H₄Cl₂ E) N₂O₅, PCl₃, HO, C₃H₂Cl

C) N₂O₅, PCl₃, H₂O₂, C₃H₂Cl₂

84. Given the following molecular formulas, determine the empirical formula of each compound: Cl₂O₅, PbCl₄, N₂O₄, C₃H₆Cl₂.

A) ClO_2.5, PbCl₄, NO₂, C₃H₆Cl₂ D) Cl₂O₅, PbCl₄, N₂O₄, C₃H₆Cl₂

B) Cl₂O₅, PbCl₄, NO₂, C₃H₆Cl₂ E) Cl₂O₅, PbCl, N₂O₄, C₃H₆Cl₂

C) Cl₂O₅, PbCl₄, NO₂, CH₂Cl

85. Given the following molecular formulas, determine the empirical formula of each compound: P₄O₁₀, SnCl₂, N₂O₃, CH₃CO₂H.

A) P₂O₅, SnCl₂, N₂O₃, CH₃CO₂H D) PO_2.5, SnCl, NO_1.5, CH₃CO₂H

B) PO_2.5, SnCl₂, N₂O₃, CH₃CO₂H E) P₄O₁₀, SnCl₄, N₂O₃, CH₂O

C) P₂O₅, SnCl₂, N₂O₃, CH₂O

86. Acetic acid is the active ingredient in vinegar. It consists of 40.00% C, 6.714% H, and 53.29% O. What is the empirical formula of acetic acid?

A) C_3.33H_6.66O_3.33 B) C₃H₆O₃ C) CH₂O D) C₂H₄O₂ E) CH₃O

87. Putrescine is a compound that is partially responsible for the rotten smell of decaying flesh. It consists of 54.50% C, 13.73% H, and 31.77% N. What is the empirical formula of putrescine?

A) C₅HN₃ B) C_4.5H_13.5N_2.3 C) C₄H₁₃N₂ D) C₂H₆N E) C₄H₁₂N₂

88. Methyl butyrate is a compound that is partially responsible for the flavor of apples. It consists of 58.80% C, 9.87% H, and 31.33% O. What is the empirical formula of methyl butyrate?

A) C₆H₁₀O₃ B) C₅H₁₀O₂ C) CH₂O D) C_4.9H_9.8O_1.9 E) C₄H₉O₂

89. Acetaminophen is the active ingredient in Tylenol. It consists of 63.56% C, 6.00% H, 9.27% N, and 21.17% O. What is the empirical formula of acetaminophen?

A) C₈H₈NO₂ B) C₈H₉NO₂ C) C₆HNO₂ D) C_5.3H_5.9N_0.7O_1.3 E) C₄H₄NO

90. Which of the following statements regarding empirical and molecular formulas is correct?

A) Information on percent composition is all that is necessary to determine both an empirical and a molecular formula.

B) A compound with an empirical formula of CH₂O and a molar mass of 90 g/mol would have a molecular formula of C₃H₆O₃.

C) The compounds C₂H₄ and C₃H₆ have different empirical formulas.

D) The formula Ca₂Cl₄ is the correct empirical formula for calcium chloride.

E) The compound benzene has a molecular formula of C₆H₆, so its empirical formula would be C₃H₃.

91. The molecular formula of the molecules in the figure is:

A) NH₄ B) N₂H₄ C) NH₃ D) N₂H₃ E) N₄H₂

92. Acetic acid has a molar mass of 60.05 g/mol and consists of 40.00% C, 6.714% H, and 53.29% O. What is the molecular formula of acetic acid?

A) C_3.33H_6.66O_3.33 B) C₃H₆O₃ C) CH₂O D) C₂H₄O₂ E) CH₃O

93. Butyric acid has a very unpleasant odor. It is present in some rotting foods, body odor and vomit. Butyric acid has a molar mass of 88.10 g/mol and consists of 54.53% C, 9.153% H, and 36.32% O. What is the molecular formula of butyric acid?

A) CH₂O_0.5 B) CH₂O C) CH₄O D) C₂H₄O E) C₄H₈O₂

94. The following minerals contain lead. Rank the minerals in order of percent lead from least to greatest: cottunite, PbCl_2;anglesite, PbSO₄; andorite, PbAgSb₃S₆; and galena, PbS.

A) PbAgSb₃S₆< PbSO₄< PbCl₂< PbS D) PbAgSb₃S₆< PbSO₄< PbS < PbCl₂

B) PbS < PbCl₂< PbSO₄< PbAgSb₃S₆ E) PbS < PbAgSb₃S₆ < PbSO₄ < PbCl₂

C) PbS < PbSO₄< PbCl₂< PbAgSb₃S₆

95. The following minerals contain silver. Rank the minerals in order of percent silver from least to greatest: miersite, AgI; hessite, Ag₂Te; empressite, AgTe; and cerargyite, AgCl.

A) AgI < AgCl < Ag₂Te < AgTe D) AgTe < AgI < AgCl < Ag₂Te

B) Ag₂Te < AgTe < AgI < AgCl E) AgTe < AgI < Ag₂Te < AgCl

C) AgCl < Ag₂Te < AgTe < AgI

96. The following minerals contain zinc. Rank the minerals in order of percent zinc from least to greatest: sphalerite, ZnS; smithsonite, ZnCO₃; zincite, ZnO; gahnite, ZnAl₂O₄.

A) ZnO < ZnS < ZnAl₂O₄< ZnCO₃ D) ZnAl₂O₄< ZnCO₃< ZnO < ZnS

B) ZnO < ZnS < ZnCO₃< ZnAl₂O₄ E) ZnCO₃< ZnAl₂O₄< ZnS < ZnO

C) ZnAl₂O₄< ZnCO₃< ZnS < ZnO

97. How much water had to be added to 10.0 mL of the first solution to obtain the second solution?

A) 10.0 mL B) 20.0 mL C) 40.0 mL D) 50.0 mL E) 500.0 mL

98. How much water had to be added to 50.0 mL of the first solution to obtain the second solution?

A) 10.0 mL B) 33.3 mL C) 50.0 mL D) 83.3 mL E) 100.0 mL

99. Calculate the molarity of a solution consisting of 60.0 g of NaOH in 1.50 L of solution.

A) 40.0 M B) 1.00 M C) 1.74 M D) 1.50 M E) 1.60 ´ 10³ M

100. Calculate the molarity of a solution consisting of 75.0 g of KOH in 2.00 L of solution.

A) 37.5 M B) 0.938 M C) 1.34 M D) 0.668 M E) 2.10 ´ 10³ M

101. Calculate the molarity of a solution consisting of 65.5 g of K₂SO₄ in 5.00 L of solution.

A) 3.81 ´ 10³ M B) 0.250 M C) 0.0752 M D) 0.376 M E) 0.125 M

102. Calculate the molarity of a solution consisting of 73.8 g NaCl in 1.50 L of solution?

A) 0.528 M B) 1.19 M C) 49.2 M D) 1.26 M E) 0.842 M

103. Calculate the moles and the mass of solute in 500.0 mL of 2.00 M HCl.

A) 2.00 moles and 73.0 g D) 1.00 mole and 0.0274 g

B) 1000 moles and 3.65 ´ 10⁴ g E) 1000 moles and 27.4 g

C) 1.00 mole and 36.5 g

104. Calculate the moles and the mass of solute in 250.0 mL of 6.00 M NaOH.

A) 6.00 moles and 240. g D) 6.00 moles and 0.0150 g

B) 1.50 moles and 60.0 g E) 24.0 moles and 0.600 g

C) 1.50 moles and 0.0375 g

105. Calculate the moles and the mass of solute in 750.0 mL of 3.00 M NaCl.

A) 2.25 moles and 132 g D) 4.00 moles and 0.0684 g

B) 2.25 moles and 0.0385 g E) 2.25 ´ 10³ moles and 38.5 g

C) 4.00 moles and 234 g

106. What mass of NaCl is present in 125.0 mL of a 0.100 M NaCl solution?

A) 125 g B) 12.5 g C) 73.1 g D) 0.731 g E) 46.8 g

107. Calculate the volume of 6.00 M NaOH that would be required to obtain 2.50 moles of the solute.

A) 15.0 L B) 0.417 mL C) 417 L D) 417 mL E) 15.0 mL

108. Calculate the volume of 12.0 M HCl that would be required to obtain 3.00 moles of the solute.

A) 2.50 ´ 10² L B) 2.50 ´ 10² mL C) 36.0 mL D) 36.0 L E) 9.11 L

109. Calculate the volume of 14.0 M HNO₃ that would be required to obtain 3.00 moles of the solute.

A) 4.67 mL B) 4.67 L C) 214 mL D) 214 L E) 13.5 L

110. How much water must be added to 500.0 mL of a 3.00 M HCl solution to obtain a solution that is 2.00 M?

A) 1.00 L B) 1.50 L C) 7.50 ´ 10²mL D) 2.50 ´ 10²mL E) 12.0 L

111. In order to prepare a 0.0500 M NaOH solution, to what volume would you dilute 25.0 mL of 2.50 M NaOH?

A) 1.25 ´ 10³ L B) 1.25 L C) 1.25 mL D) 0.0625 L E) 0.500 L

112. If 50.0 mL of 0.235 M NaCl solution is diluted to 200.0 mL, what is the concentration of the diluted solution?

A) 0.0588 M B) 0.0118 M C) 58.8 M D) 1.18 M E) 0.0426 M

113. If 100.0 mL of 0.426 M NaOH solution is diluted to 500.0 mL, what is the concentration of the diluted solution?

A) 0.0426 M B) 0.0852 M C) 0.117 M D) 2.13 M E) 8.52 ´ 10³ M

114. One mole of methane (CH₄) and one mole of oxygen (O₂) would have the same number of atoms.

115. A formula written with the simplest ratio of atoms or ions is called a molecular formula.

116. The substance in the figure with the most atoms per mole is NaCl.

117. Of the substances shown in the figure, only N₂O₃ has an empirical formula that is the same as its molecular formula.

118. The solute in the solution shown in the figure is CaCl.

119. Image B in the figure shows a more concentrated solution because there are more water molecules.

120. The process of diluting a solution in the laboratory is much like preparing juice from a canned concentrate of the juice.

121. Molarity is defined as the moles of solute divided by the liters of solvent.

122. To obtain 0.50 moles of potassium nitrate from a solution, you could either use 100.0 mL of a 5.0 M solution, or 250.0 mL of a 2.0 M solution.

123. How many moles atoms of iron are in 26.5 g of Fe₂O₃?

124. How many grams atoms of iron are in 26.5 g of Fe₂O₃?

125. How many atoms of iron are in 26.5 g of Fe₂O₃?

126. What is the formula of the molecule in the figure (a) below?

127. What is the formula of the molecule in the figure (b) below?

128. What is the formula of the molecule in the figure (c) below?

129. How many sulfur atoms are in 0.25 mole of SO₃?

130. How many oxygen atoms are in 0.25 mole of SO₃?

131. Calculate the molar mass of CsCl in the figure below.

132. Calculate the molar mass of O₂ in the figure below.

133. Calculate the molar mass of SO₂ in the figure below.

menu

Chapter 4: Chemical Composition 1) A 5

Chemistry