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 10²¹Se 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 10²⁰Cd atoms

b) 6.01 x 10²³ Sb atoms

c) 9.43 x 10²⁶F 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.