1
Unit 5A Chemical Quantities
Name: _________________________________
1. How many atoms of arsenic (As) are present in a sample containing 155 moles of arsenic (As)?
2. If a chemist has determined that he has a sample containing 1.24 x 1025 atoms of silicon (Si), how many moles of
silicon (Si) are in the sample?
3. How many atoms of magnesium (Mg) are present in 0.780 moles magnesium (Mg)?
4. How many moles of carbon monoxide (CO) would contain 1.24 x 1023 molecules of carbon monoxide (CO)?
5. How many molecules of diphosphorous tetroxide (P2O4) are in 15.0 moles of P2O4?
6. How many atoms of sodium are in 1 mole of sodium?
7. How many atoms of chlorine are present in 25 molecules of carbon tetrachloride (CCl4)?
8. How many atoms of hydrogen are in 6 molecules of CH3Cl?
9.
How is asking someone, “how many atoms are in 25 molecules of CO2” different from asking the person, “how
many atoms are in 25 moles of CO2”?
2
10. How many molecules of glucose (C6H12O6) are in 1 mole of C6H12O6?
11. How many atoms of oxygen are in 1 mole of O2?
12. How many molecules of oxygen are in 1 mole of O2?
13. How many moles of sulfur would contain 1.37 x 1022 atoms of sulfur?
14. In 1 mole of H2, how many atoms of hydrogen are there?
15. In 1 mole of F2, how many molecules of fluorine are there?
16. An incandescent light bulb contains 0.00100 moles of tungsten. How many tungsten atoms are in the light bulb?
17. How many molecules of bromine are in 10.0 mole of Br2?
18. How many molecules of formaldehyde (CH2O) are in 10.0 moles of CH2O?
19. How many molecules of diphosphorous trioxide (P2O3) are in 10.0 moles of P2O3?
3
20. What is the molar mass of diphosphorous trioxide (P2O3)?
21. What is the molar mass of Ca3(PO4)2?
22. What is the mass of 1 mole of nitrogen atoms?
23. What is the mass of 1 mole of nitrogen molecules?
24. What is the molar mass of nitrogen gas?
25. What is the molar mass of Na2O?
26. What is the mass of 1 mole of Na2O?
27. What is the molar mass of oxygen gas?
28. What is the mass of 1 mole of oxygen atoms?
29. What is the mass of sulfur hexafluoride (SF6) in 1.55 moles sulfur hexafluoride?
30. True or False: In Q # 20 – 29, you were asked to calculate the molar mass; but, in Q # 27, you were asked to use the
molar mass in order to calculate something else. _________
4
31. A sample of lead(II) nitrate, Pb(NO3)2, has a mass of 150.00 grams. How many moles of lead(II) nitrate does the
sample contain?
32. Calculate the mass of 3.42 moles of Cu(C2O4)2.
33. Calculate the mass of 3.91 moles of Al(HCO3)3.
34. How many moles of helium are there in a 25.50 gram sample of helium?
35. A sample of Pb(NO3)2 has a mass of 150.00 grams. How many moles does the sample contain?
36. A sample of 43.60 grams of Al2(CO3)3 contains how many moles?
37. How many moles of gold are present in a sample having a mass of 592.00 grams?
38. How many moles of calcium acetate are in a sample of 38.90 grams of Ca(C2H3O2)2?
5
39. What temperature is standard temperature in Kelvins?
40. What temperature is standard temperature in 0C?
41. What pressure is standard pressure in kPa?
42. What pressure is standard pressure in atm?
43. The molar volume of nitrogen gas at STP is what?
44. What is the volume of 16.9 moles of helium at STP?
45. How many moles of He are in a volume of 0.500 L at STP?
46. What is the volume at STP of 0.2470 moles argon?
47. How many moles of Ar are in 335.2 Liters of argon at STP?
48. How many liters of CO2 gas was required if a scientist used 0.0957 moles of CO2 at STP?
49. What would be the volume of a sphere that contains 750.0 moles of chlorine gas at STP?
50. How many moles of NO2 gas have a volume of 50.0 Liters at STP?
51. An incandescent light bulb holds about 0.0250 Liters of argon at STP. How many moles of argon gas are in the
bulb?
6
52. . What is the molar mass of an unknown gas, whose density at STP = 0.089 g/L?
53. What is the density at STP of an unknown gas whose molar mass = 46.01 g/mol?
54. What is the density at STP of NO2?
55. What is the molar mass of an unknown gas whose density at STP= 3.21 g/L?
56. What is the density of Neon at STP?
57. What is the molar mass of an unknown gas at STP if its density = 1.964 g/L?
58. What is the density of Argon gas at STP?
59. What is the molar mass of an unknown gas whose density at STP is 1.25 g/L
60. What is the density of Neon at STP?
7
61. How many molecules of N2O4 would there be in 50.0 Liters of N2O4 gas at STP?
62. How many grams of hydrogen (H2) would be produced in a lab in which students generated 50.0 Liters hydrogen
gas? Assume STP.
63. If 100.00 grams of Neon is used during the manufacture of a large neon sign, what volume (at STP) of gas was
used?
64. If you use 2 heaping teaspoons of table sugar to sweeten your coffee, you are using approximately 12.00 grams
of sugar (C12H22O11). How many molecules of sugar are you using as you sweeten your beverage?
65. The mass of a nickel is 5.00 grams.
A. If nickels were entirely made of the element nickel, how many atoms of nickel would there be in 1 nickel?
B. A nickel is actually 25% by mass nickel. How many atoms of nickel are actually in a nickel.
66. What volume of methane, CH4, is used if 2.50 x 10 25 molecules of methane are burned during a student lab?
8
67. When a chemist uses 212.50 grams of P2O5 as the drying agent for a desiccator, how many molecules of the
compound are used?
68. Approximately 3.2 x 10 6 liters of air could be contained within Disney’s giant Mickey “hot air” balloon.
Approximately many molecules of air might be contained in the huge balloon, if the balloon were placed in STP
conditions?
69. When under STP conditions, the volume of a helium balloon is 2.00 Liters. What is the mass of helium in the
balloon?
70. The mass of a flute is approximately 500.00 grams. Assuming that the flute is primarily made of silver (the mass of
the non-silver parts is negligible), about how many atoms of silver are in a flute?
71. A gold nugget that will used by a jeweler to make a gold ring has a mass of 20.00 grams. If the jeweler uses all of
the nugget, how many atoms of gold will be in the ring?
72. The liquid propane (C3H8) tanks that are used to store the fuel for back yard grills contain about 9,000. grams of
C3H8. If the propane were transferred from a tank to a flexible “balloon” container, and the flexible container were
moved into STP conditions, what would be the new volume of the gas?