# 6.E: Homework Chapter 6

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Conversion Factors

1. Write out conversion factors between the moles of each element and the moles of the compound C5H12.

2. Write out conversion factors between the moles of each element and the moles of the compound C27H46O.

3. Write out conversion factors between the moles of each element and the moles of the compound C6H12O6.

4. Write out the conversion factor of the given element in the given compound using the mass percent composition.

a) Carbon dioxide is 27.19% carbon by mass

b) Butane is 17.34% hydrogen by mass

c) C6H8O7 is 58.29% oxygen by mass

5. Write out the conversion factor of the given element in the given compound using the mass percent composition.

a) Ethanol is 13.13% hydrogen by mass

b) Aluminum nitrate is 19.73% nitrogen by mass

c) Methyl butanoate is 58.8% carbon by mass

6. Write out the conversion factor of the given element in the given compound using the mass percent composition.

a) Propane is 81.68% carbon by mass

b) Ethylene is 14.14% hydrogen by mass

c) Aluminum oxide is 52.9% aluminum by mass

The Mole Concept

7. How many moles of atoms are in the following?

a) 8.22 x 1024 As atoms

b) 4.41 x 1022 Ne atoms

c) 6.77 x 1023 Li atoms

d) 2.10 x 1021 S atoms

8. How many atoms are in the following given numbers of moles of an element?

a) 0.994 mol F

b) 4.39 mol Sr

c) 9.1 x 10-3 mol B

d) 13.8 mol Cl

9.  How many moles of atoms are in the following?

a) 2.13 x 1025 He atoms

b) 3.65 x 1022 Ga atoms

c) 6.022 x 1023 Mg atoms

d) 1.04 x 1024 Cu atoms

10. Complete the table:

 Element Moles Number of Atoms Se 0.0112 K 1.55 x 1023 Ti 2.34 Br 7.12 x 1022

11. Complete the table:

 Element Moles Number of Atoms P 13.2 Au 0.222 F 5.02 x 1024 Be 1.98 x 1023

12. Complete the table:

 Element Moles Number of Atoms O 9.54 x 1021 Zr 1.30 x 10-6 Bk 25.3 Ba 7.71 x 1024

13. Complete the table:

 Element Moles Mass N 75.4g W 13.9g Ge 0.00784 Rb 4.09

14. Complete the table:

 Element Moles Mass Co 62.4g Hg 2.23 x 10-4 Te 18.6 Al 4.97g

15. Complete the table:

 Element Moles Mass Li 244 Y 0.653 B 20.7g He 0.00422g

16. Calculate the mass in grams of the following:

a) 4.45 x 1019 Ag atoms

b) 5.50 x 1024 Bi atoms

c) 2.08 x 1021 Se atoms

d) 7.31 x 1024 Ar atoms

17. Calculate the number of atoms in each of the following:

a) 14.8g Al

b) 3.98g Ca

c) 1.90g Co

d) 26.7g S

18. Calculate the mass of the following:

a) 3.72 x 1020 Cd atoms

b) 6.01 x 1023 Sb atoms

c) 9.43 x 1026 F atoms

d) 2.84 x 1022 Re atoms

19. Complete the table:

 Element Mass Moles Number of Atoms Sn 3.65 Xe 0.0983 H 65.5mg Si 4.35 x 1024

20. Complete the table:

 Element Mass Moles Number of Atoms Ca 6.18 x 1021 Br 0.138kg Ga 9.29 x 1023 K 10.4

21. Complete the table:

 Element Mass Moles Number of Atoms Be 226mg S 7.36 x 1020 Nb 0.104 N 0.00391kg

22. Calculate the mass of the following in grams:

a) 6.10 mol carbon monoxide

b) 0.364 mol sulfur hexafluoride

c) 4.44 mol potassium hydroxide

d) 1.71 mol lithium nitrate

23. Calculate the mass of the following in grams:

a) 13.4 mol sodium chloride

b) 0.223 kmol nitrogen dioxide

c) 0.00322 mol boron tribromide

d) 144 mmol xenon tetroxide

24. Calculate the number of moles of molecules for the following:

a) 29.8g ammonium iodide

b) 8.34g potassium cyanide

c) 3.50mg sodium sulfate

d) 0.0888kg hydrochloric acid

25. Complete the table:

 Compound Mass Moles Number of Molecules H2SO4 188kg NaBr 0.318 KClO3 4.05mg NH3 7.10

26. Complete the table:

 Compound Mass Moles Number of Molecules NO 0.929 CCl4 0.133kg HF 16.9g CS2 0.00268

27. Complete the table:

 Compound Mass Moles Number of Molecules CH4 3.45 NaOH 42.2mg LiCl 0.00215 AgNO3 311g

28. Calculate the mass of the following in grams:

a) 3.19 x 1024 SrCl2 formula units

b) 2.81 x 1021 Na3PO4 formula units

c) 7.70 x 1022 KBrO3 formula units

d) 4.51 x 1019 HNO3 formula units

29. Calculate the mass of the following in grams:

a) 4.30 x 1023 KCN formula units

b) 6.25 x 1025 FeCl3 formula units

c) 9.64 x 1022 HF molecules

d) 7.38 x 1018 CO2 molecules

30. Calculate the number of molecules of the following:

a) 13.2g SO2

b) 9.03g CH4

c) 0.00888g H2

d) 157g LiBr

31. A sample of CuS has a mass of 0.67mg. Calculate the number of formula units.

32. A sample of VF4 has a mass of 0.0076kg. Calculate the number of formula units.

33. A sample of C6H6 has a mass of 15ng. Calculate the number of molecules.

Chemical Formulas as Conversion Factors

34. Calculate the number of moles of O in the following:

a) 11.4 mol CO2

b) 0.761 mol H2O

c) 4.08 mol N2O5

d) 0.302 mol HNO3

35. Calculate the number of moles of H in the following:

a) 1.44 mol H2SO4

b) 0.00373 mol C3H8

c) 22.4 mol HNO2

d) 0.0200 mol C3H9N

36. How many moles of H are in 1.85 mol [Cr(OH2)5Cl] Cl•H2O?

37. Calculate the mass in kg of the following which each contain 3.5 x 102 kg of lithium.

a) Li2SO4

b) LiOH

c) LiBr

38. Calculate the mass in mg of the following which each contain 2.2 x 104 mg of silver.

a) Ag2O

b) AgI

c) Ag3N

39. Calculate the mass in kg of the following which each contain 7.1 x 102kg of sodium.

a) NaCl

b) Na2CO3

c) Na3PO4

40. Which of the following contains the greatest number of moles of oxygen? Show all work.

a) 3.03 mol C2H6O2

b) 16.9 mol N2O3

c) 8.27 mol Sr(NO3)2

d) 0.0180 mol BaSO4

41. Which of the following contains the greatest number of moles of hydrogen?

a) 0.712 mol C3H6O3

b) 2.40 mol H2O

c) 3.49 mol C4H10

d) 7.48 mol NH4OH

42. Of the following compounds containing the ammonium ion, which contains the greatest number of moles of nitrogen? Show all work.

a) 11.4 mol NH4NO3

b) 9.65 mol (NH4)2O

c) 83.4 mol NH4I

d) 0.997 mol (NH4)3PO4

Mass Percent Composition

43. An 8.91g sample of an organic compound is found to contain 3.34g C, 0.98g H, 2.61g O, and 1.98g N. Determine the mass percent of each element.

44. BaSO4 is approximately 58.84% barium by mass. Calculate the mass of barium in grams in a 7.22g sample of BaSO4.

45. Calculate the mass percent composition of oxygen in the following compounds.

a) CrO3

b) SO2

c) NaOH

d) Al2(SO4)3

46. Calculate the mass percent composition of all the individual elements in each of the following compounds.

a) SrCl2

b) Fe2O3

c) CsF

d) NaCN

47. Calculate the mass percent composition of all the individual elements in each of the following compounds.

a) HClO3

b) AgBr

c) PbSO4

d) CH4

48. Calculate the mass percent composition of all the individual elements in each of the following compounds.

a) Be3N2

b) IF7

c) ZnF2

d) Ca(OH)2

Calculating Empirical Formulas

49. An organic compound is found to have 36.03g of carbon, 6.048g hydrogen, and 16.00g oxygen. Determine the empirical formula of the organic compound.

50. An organic compound is found to have 32.07g of carbon, 3.36g of hydrogen, 18.63g of nitrogen, and 10.72g of oxygen. Determine the empirical formula of the organic compound.

51. An organic compound is found to have 15.97g of carbon, 2.016g of hydrogen, and 21.28g of oxygen. Determine the empirical formula of the organic compound.

52. The nonsteroidal anti-inflammatory drug Ibuprofen consists of 75.69% carbon, 8.80% hydrogen, and 15.51% oxygen. Determine the empirical formula of ibuprofen.

53. The chemical compound cinnamaldehyde is what gives cinnamon its flavor and odor. When tested in a lab, it is found to consist of 81.79% carbon, 6.10% hydrogen, and 12.11% oxygen. Determine the empirical formula of cinnamaldehyde.

54. The antiviral drug zanamivir is used in influenza vaccinations. It consists of 43.37% carbon, 6.07% hydrogen, 16.86% nitrogen, and 33.70% oxygen. Determine the empirical formula of zanamivir.

Calculating Molecular Formulas

55. Determine the molecular formula of each of the following using the given empirical formulas and total molar masses.

a) CO2H, 225.09g/mol

b) CClN, 184.41g/mol

c) C2H3O, 86.09g/mol

d) C4H8O, 144.21g/mol

56. Determine the molecular formula of each of the following using the given empirical formulas and total molar masses.

a) C5H8, 136.23 g/mol

b) CH3O4P, 660.02 g/mol

c) C2H5N, 86.14g/mol

d) CH, 78.11g/mol

57. Determine the molecular formula of each of the following using the given empirical formulas and total molar masses.

a) C6H8O, 288.37g/mol

b) CH2N2O2, 296.18g/mol

c) C2H7NS, 77.16g/mol

d) C11H22O, 340.57g/mol

Challenge Problems

58. How many ethanol molecules are in a 613mL container of pure ethanol? Ethanol has a density of 0.7893 g/cm3.

59. Complete the table:

 Substance Mass Moles Number of Particles CdF2 0.0389 N 17.3mg Ag 1.02kg HNO3 4.55 x 1021

60. Complete the table:

 Formula Name Mass %Na %Cl %O NaClO2 NaClO3 NaClO4

61. Aldrin is an insecticide that was commonly used in soil fields until it was banned in many countries. It is found to consist of 39.50% carbon, 2.21% hydrogen, and 58.29% chlorine. Its molar mass is 364.884g/mol. Using this information, determine the molecular formula of Aldrin.

62. A solution contains approximately 45.4% KBr by mass within it. The solution has a density of 2.21g/mL. What volume of the solution contains 2.0g of potassium?

63. A sample of an acid is analyzed in a laboratory and is found to consist of 40.00% C, 6.71% H, and 53.29% O. Its molar mass is 90.078g/mol. Determine the acid’s molecular compound. Search the formula in your text or an internet source and write its name.

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