The Mole
Name________________________________
Period______Date______________________
Find the atomic mass of the following elements:
1. Zn ______________
2. N ______________
3. CH2Cl2______________
4. NaCl______________
5. HNO3______________
6. NaOH______________
7. CuSO4  5H2O______________
8. Fe(C2H3O2)3______________
Find the mass of the following substances:
9. 0.50 mol of Ca(ClO3)2
10. 0.152 mol phosphoric acid
11. 0.418 mol iron (III) nitrate
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Find the amount of moles of the following substances:
12. 50.00 g of C6H12O6
13. 15.57 g of Bi(OH)3
14. 0.572 g of calcium phosphide
Find the number of particles (atoms, molecules or formula units) of each substance:
15. 0.593 mol aluminum sulfate
16. 0.2770 mol of sulfuric acid
17. 3.552 mol of iron
Find the number of moles of each substance:
18. 2.45 x 1021 atoms of copper
19. 4.957 x 1028 formula units of calcium phosphate
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20. 7.660 x 1019 molecules of diphosphorus pentoxide
DIRECTIONS: Show all your work in solving the following. Box your final answer with a unit and the
correct number of significant digits.
21. Find the mass of 0.89 mol of calcium chloride.
22. A bottle of lead (II) sulfate contains 158.1 g of the compound. How many moles of the substance are in
the bottle?
23. Find the mass of 1.112 mol of hydrogen fluoride.
24. Determine the number of moles of C5H12 that are in 362.8 g of the compound.
25. Determine the number of atoms that are in 0.58 mol of selenium.
26. How many moles of barium nitrate contain 6.8 x 1024 formula units?
27. Determine the number of atoms that are in 1.25 mol of oxygen gas.
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28. How many moles of magnesium bromide contain 5.38 x 1024 formula units?
29. Determine the number of formula units that are in 0.668 mol of silver nitrate.
30. How many moles of ethane, C2H6, contain 8.46 x 1024 molecules?
31. Determine the number of formula units that are in 1.48 mol of sodium fluoride.
32. A tube with a volume of 3.68 L contains how many moles of neon gas at STP?
33. A container holds 4.51 moles of argon gas. What is the volume of this container at STP?
DIRECTIONS: Show all your work in solving the following. Box your final answer with a unit and the
correct number of significant digits.
34. How many formula units are in 3.5 g of sodium hydroxide?
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35. If you burned 6.10 x 1024 molecules of ethane, C2H6, what mass of ethane did you burn?
36. How many formula units are in 5.1 g of titanium (IV) oxide?
37. What is the mass of 3.62 x 1024 molecules of methanol, CH3OH?
38. How many formula units are in 1.4 g of lead (II) chloride?
39. Determine the mass of 9.24 x 1024 molecules of decane, C10H22.
40. How many molecules are in 5.6 g of H2S?
41. A chemical reaction produces 7.02 L of carbon dioxide gas at STP. What mass of carbon dioxide gas was
produced?
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42. A chemical reaction produces 0.750 L of hydrosulfuric acid in the gaseous state at STP. What mass of
gas is produced?
43. 12.1 g of dry ice (solid carbon dioxide) is converted to a gas. What volume will that gas occupy at STP?
Empirical Formulas
44. A compound was analyzed and was found to contain 9.8 g of nitrogen, 0.7 g of hydrogen, and 33.6 g of
oxygen. What is the empirical formula of the compound?
45. Determine the empirical formula of a compound containing 3.6 g of carbon, 0.9 g of hydrogen, and 2.4 g
of oxygen.
46. Determine the empirical formula of a compound containing 1.37 g of barium, 0.32 g of sulfur, and 0.64 g
of oxygen.
47. Determine the empirical formula of a compound containing 2.644 g of gold and 0.476 g of chlorine.
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48. Determine the empirical formula of a compound containing 0.928 g of gallium and 0.412 g of phosphorus.
49. Determine the empirical formula of a compound containing 1.723 g of carbon, 0.289 g of hydrogen, and
0.459 g of oxygen.
50. Find the empirical formula of a compound, given that the compound is found to be 47.9% zinc and 52.1%
chlorine by mass.
51. Find the empirical formula of a compound, given that a 48.5 g sample of the compound contains 1.75 g
carbon and 46.75 g bromine.
52. Determine the empirical formula of a compound containing 20.23% aluminum and 79.77% chlorine.
53. Determine the empirical formula of a compound containing 24.74% potassium, 34.76% manganese, and
40.50% oxygen.
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54. Determine the empirical formula of a compound containing 4.288 g of carbon and 5.712 g of oxygen.
55. Determine the empirical formula of a compound containing 3.611 g of calcium and 6.389 g of chlorine.
Molecular Formulas
56. A certain sugar has a chemical composition of 40.% carbon, 6.6% hydrogen, and 53.3% oxygen. The
molar mass is 180. g/mol. What is the molecular formula?
57. The neurotransmitter norepinephine is 56.8% carbon, 6.5 % hydrogen, 8.3% nitrogen and 28.4% oxygen.
Its molar mass is 169 g/mol. Find the molecular formula of this substance.
58. Find the molecular formula of a compound that contains 42.56 g of palladium and 0.80 g of hydrogen.
The molar mass of the compound is 216.8 g/mol.
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59. Find the molecular formula of a compound that contains 30.45% nitrogen and 69.55% oxygen. The molar
mass of the compound is 92.02 g/mol.
60. Find the molecular formula of a compound, given that a 212.1 g sample of the compound contains 42.4 g
of hydrogen and 169.7 g of carbon, and the molar mass is 30.0 g/mol.
61. A compound is known to have a molar mass of 391.5 g/mol. Find the molecular formula of this
compound, given the results of an analysis of a 310.8 g sample that revealed that the sample contains only
boron and iodine. The mass of iodine in the sample was found to be 302.2 g.
% Composition:
62.
What is the percent composition of ammonium phosphate?
63. What is the percent composition of silicon dioxide?
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64. What is the percent composition of calcium carbonate?
65. A sample of iron oxide has a mass of 1.596 g. On analysis, it was found to contain 1.116 g of iron and
0.48 g of oxygen. Find the percentage composition of this compound.
66. Find the percentage composition of a compound that contains 17.6 g of iron and 10.3 g of sulfur. The
total mass of the compound is 27.9 g.
67. Find the percentage composition of a compound containing 32.0 g of bromine and 4.9 g of magnesium.
68. Find the percentage composition of a compound that contains 1.94 g of carbon, 0.48 g of hydrogen, and
2.58 g of sulfur in a 5.00 g sample of the compound.
69. A sample of an unknown compound with a mass of 0.847 g has the following composition: 50.51%
fluorine and 49.49% iron. When this compound is decomposed into its elements, what mass of each
element would be recovered?
70. Find the percentage composition of a compound that contains 2.630 g of carbon, 0.370 g of hydrogen, and
0.580 g of oxygen in a 3.58 g sample of the compound.
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The Mole Review
Directions: Complete the following problems. Make sure to show all work and use the correct number
of significant digits and put units on every number.
71. Determine the formula mass of aluminum chloride: ____________________
72. Determine the molar mass of magnesium hydroxide: ________________________
73. What is the mass of 0.882 moles of O2?
74. How many formula units make up 4.5 g of calcium hydroxide?
75. Convert 2.67 x 1022 atoms of Na to moles of Na.
76. Find the number of grams of hydrogen gas in 7.17 x 1022 molecules of hydrogen gas.
77. What volume will 57 grams of CO2 gas occupy at STP?
78. Determine the percentage composition of aluminum sulfate.
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79. A sample of an unknown compound with a mass of 2.876 g has the following composition: 66.07%
carbon, 6.71% hydrogen, 4.06% nitrogen, and 23.16% oxygen. What is the mass of each element in this
compound?
80. Find the empirical formula for a compound which contains 6.5 g potassium, 5.9 g chlorine, and 8.0 g
oxygen.
81. A sample of ethane is made up of 85.7 g of carbon and 14.3 g of hydrogen. If the molar mass is 28.0
g/mol, what is the molecular formula?
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