Chemistry I Accelerated Study Guideline - Chapter Ten The Mole _____________________________________________________________________________________________
By the end of this chapter the skills you should be able to demonstrate are: 1. Name the basic SI unit for measuring the amount of a substance. 2. Distinguish between the terms gram atomic mass, gram molecular mass, and gram formula mass. 3. Define the relationship between the gram formula mass and the molar mass of a substance. 4. Explain the centrality of the mole to chemical calculations. 5. Convert using the mole between mass, number of particles, molarity and volumes of gas at STP. 6. Calculate the percent composition of a substance from its chemical formula or experimental data. 7. Derive the empirical formula of a compound from experimental data. 8. Derive the molecular formula of a compound from experimental data. 9. Determine the formulas of hydrates.
Suggested Problems: p.316-318 #76, 77, 80, 81, 83, 87, 88, 89, 90, 92, 93
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Video Worksheet: The Mole Please Answer the following questions while you watch the video 1. What is the most basic kind of matter?
2. What is the motto of the same number trucking company?
3. What type of substance behaves as if its particles do not touch?
4. What are conditions must exist in order so a container can hold the same number of gas particles?
5. What does the Law of Combining Volumes state?
6. What is Avogadro’s hypothesis?
7. What did Avogadro say about gas particles?
8. What is Relative Molecular Mass?
9. For many years, what served as the standard for relative molecular mass?
10. What is the modern machine that can determine the relative atomic mass of elements?
11. What is an isotope of an atom?
12. What is the standard today for relative atomic mass?
13. What is the volume of a mole of gas particles at standard temperature and pressure?
14. What is Avogadro’s number in scientific notation? page 2
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Basic Mole Problems Calculate the number of moles in each of these 1.
23
6.02 X 10
atoms of lithium 23
6.02 X 10
atoms Li
X
1 mole Li 23
6.02 X 10 2.
24
1.204 X 10
atoms Li
molecules of nitrogen 24
1.204 X 10
molecules N2
X
1 mole N2 23
6.02 X 10 24
= 1.00 mole Li
3.
1.806 X 10
4.
6.00 X 10 formula units of potassium chloride
5.
2.00 X 10
6.
2.408 X 10
7.
3.01 X 10
8.
1.50 X 10
9.
1.00 X 10
10.
3000.0 molecules of methane
= 2.000 moles N2
molecules N2
molecules of hydrogen peroxide
5
23
molecules of beryllium oxide
24
24
22
10
molecules of aluminum phosphide
molecules of carbon dioxide
molecules of Lead(II) iodide
molecules of bromine
Calculate the number of atoms in each of these 1.
1.00 mole of gold 1.00 mole Au
2.
X
23
23
6.02 X 10 atoms Au = 6.02 X 10 1 mole Au
2.00 moles of lead page 3
atoms Au
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3.
0.500 moles of ethanol
4.
3.00 moles of sodium bromide
5.
0.020 moles of zinc chloride
6.
3.00 moles of potassium nitrate
7.
0.40 moles of sodium phosphate
8.
1.00 mole of Tin(IV) fluoride
9.
0.25 moles of oxygen
10.
4.00 moles of carbon dioxide
Calculate the molar mass of each of these 1. Silver chloride
2. Sodium hydroxide
3. Propane
4. Octane
5. Benzene
6. Copper(II) sulfate
7. methylamine (CH3NH2)
8. Ethandiol (C2H6O2)
9. Chloroform (CHCl3)
10. Tribromosilane (SiHBr3)
11. Sulfurous Acid
12. Ammonium phosphide
page 4
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Calculate the number of grams in each of these 1.
2.
1.00 mole of Boron 1.00 mole B
X
10.8 g B = 10.8 g B 1 mole B
2.00 moles of Copper 2.00 mole Cu X
63.5 g Cu = 127 g Cu 1 mole Cu
3. 0.500 moles of Neon
4. 3.00 moles of Sodium Fluoride
5. 1.00 mole of glucose
6. 4.00 moles of nitrogen
7. 0.25 moles of magnesium oxide
8. 5.00 moles of calcium chloride
9. 0.300 moles of aluminum sulfide
10. 10.00 moles of water
Calculate the number of moles in each of these 1.
2.
12.0 g of carbon 12.0 g C X
1 mole C = 1.00 mole C 12 g C
89.4 g of lithium oxide 89.4 g Li2O
X
1 mole Li2O = 3.00 moles Li2O 29.8 g Li2O
3.
5.60 g of magnesium sulfide
page 5
ChemIAcc-12Mole WS 4.
74.0 g of potassium phosphide
5.
256 g of sulfur dioxide
6.
26 g of calcium fluoride
7.
56 g of copper(II) bromide
8.
23.2 g of diboron trioxide
9.
840.0 g of aluminum flouride
10.
23.2 g of sodium chloride
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Convert each of these to moles 23
1.
6.02 x 10
molecules of carbon dioxide
2.
1.806 x 10
3.
1.51 x 10
molecules of water
3. _______________
4.
1001 molecules of tetraphosphorus decoxide
4. _______________
5.
1.00 molecule of ammonia
5. _______________
6.
34.0 grams of ammonia
6. _______________
7.
50.0 grams of calcium carbonate
7. _______________
8.
36 grams of water
8. _______________
23
23
1. _______________
molecules of chlorine
2. _______________
page 6
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9.
9.00 grams of sulfuric acid
9. _______________
10.
1.00 gram of sodium chloride
10. ______________
11.
158.1 grams of lead(II) sulfate
11. ______________
12.
362.8 grams of pentane
12. ______________
13.
12.35 grams of C4H8O2
13. ______________
14.
66.38 grams of potassium permanganate
14. ______________
15.
6.80 x 10
16.
5.38 x 10
17.
8.46 x 10
24
24
24
formula units of barium nitrate
15. ______________
formula units of magnesium bromide
16. ______________
molecules of ethane
17. ______________
Convert each of these to mass in grams 18.
5.0 moles of ammonia
18. ______________
19.
4.50 moles of sodium chloride
19. ______________
20.
0.300 moles of hydrochloric acid
20. ______________
21.
0.00200 moles of sodium sulfate
21. ______________
22.
1.50 x 10
23.
0.890 moles of calcium chloride
23. ______________
24.
1.112 moles of hydrofluoric acid
24. ______________
–4
moles of silver chloride
22. ______________
page 7
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25.
0.159 moles of silicon dioxide
25. ______________
26.
3.66 moles of nitrogen
26. ______________
Convert each of these to numbers of atoms 27.
0.400 moles of sulfur
27. ______________
28.
2.30 moles of silver
28. ______________
29.
2.0 moles of carbon dioxide
29. ______________
30.
1.8 moles of phosphorous trichloride
30. ______________
31.
35.0 moles of ammonia
31. ______________
32.
0.0500 moles of sulfur dioxide
32. ______________
33.
1.00 x 10
34.
0.580 moles of selenium
34. ______________
35
1.25 moles of oxygen
35. ______________
36.
0.688 moles of silver nitrate
36. ______________
37.
1.48 moles of sodium fluoride
37. ______________
–3
moles of carbon monoxide
33. ______________
One step volume problems 38.
How many moles are in 893 L of air at STP?
38. ______________
39.
What is the volume of 0.374 moles of nitrogen gas at STP?
39. ______________
40.
How many moles of oxygen gas are in 694 L at STP?
40. ______________
page 8
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41.
What is the volume of 13.8 moles of carbon monoxide gas at STP?
41. ______________
42.
How many moles of neon gas are in 3.68 L at STP?
42. ______________
43.
What is the volume of 0.884 moles of hydrosulfuric acid gas at STP?
43. ______________
44.
How many moles of argon gas are in 101 L at STP?
44. ______________
45.
What is the volume of 138 moles of hydrobromic acid gas at STP?
45. ______________
Two step mole problems 46.
How many formula units are in 3.5 grams of sodium hydroxide?
47.
How many grams are in 6.10 x 10
48.
How many formula units are in 5.1 grams of titanium(IV) oxide?
49.
What is the mass of 3.62 x 10
50.
How many formula units are in 1.47 grams of lead(II) chloride?
51.
What is the mass of 2.94 x 10
24
24
24
molecules of ethane?
molecules of methanol?
molecules of decane?
page 9
46. ______________
47. ______________
48. ______________
49. ______________
50. ______________
51. ______________
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52.
How many formula units are in 5.62 grams of hydrosulfuric acid?
52. ______________
53.
How many atoms are in a tank that has 5.00 mol of nitrogen dioxide gas?
53. ______________
54.
How many formula units are in 3.00 grams of sodium chloride?
54. ______________
55.
How many molecules are in 30.6 grams of butanol?
55. ______________
56.
How many atoms are in 500.0 L of helium at STP?
56. ______________
57.
If 12.1 grams of dry ice (carbon dioxide) are converted into gas at STP, what volume would it fill?
57. ______________
Molarity 1.
2.
What mass of potassium phosphate is needed to prepare 4.00 liters of 1.50 M solution?
1. _______________
What mass of 2-pentanol is needed to prepare 1.50 liters of 3.00 M solution?
2. _______________
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ChemIAcc-12Mole WS 3.
4.
5.
6.
7.
8.
9.
10.
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What volume in µL of 1.40 M acetic acid solution can be prepared using 0.400 moles of acetic acid?
3. _______________
What is the molarity of a solution that contains 85.0 grams of sodium sulfate in 325 mL of solution?
4. _______________
What is the molarity of a solution that contains 215 grams of aluminum sulfate in 2.75 cubic decimeters of solution?
5. _______________
What volume in µL of 0.750 M solution can be prepared using 18.5 grams of sodium hydroxide?
6. _______________
What is the molarity of a solution that contains 125 grams of ethanol in 0.250 cubic decimeters of solution?
7. _______________
What volume of 0.750 M solution can be prepared using 90.0 grams of ammonium chloride?
8. _______________
What is the molarity of a solution that contains 145 grams of sodium chloride in 275 mL of solution?
9. _______________
How many grams of potassium chloride are needed to prepare 0.750 L of a 1.50 M solution?
10. ______________
page 11
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What is the molarity of a solution that contains 85.6 grams of 3
hydrochloric acid in 0.385 dm of solution?
12.
How many grams of sodium hydroxide are needed to prepare 3
3.00 dm of a 1.90 M solution?
13.
12. ______________
What is the molarity of a solution that contains 8.77 grams of 3
potassium iodide in 4.75 dm of solution?
14.
15.
How many grams of iron(III) chloride are needed to prepare 2.00 L of a 3.00 M solution?
13. ______________
14. ______________
What is the molarity of a solution that contains 14.1 grams of 3
ammonia in 0.100 dm of solution?
16.
11. ______________
15. ______________
How many grams of potassium hydroxide are needed to prepare 10.5 L of a 2.50 M solution?
page 12
16. ______________
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Percent composition 1. Find the percent composition of a compound that contains 1.94 g of carbon, 0.480 g of hydrogen and 2.58 g of sulfur in a 5.00-g sample of the compound
2. A sample of an unknown compound with a mass of 0.847 g has 50.51 percent fluorine and 49.49 percent iron. If the compound is decomposed, how much of each element will be recovered?
3. Find the percent composition of a compound that contains 2.63 g of carbon, 0.370 g of hydrogen and 0.580 g of oxygen.
4. A sample of an unknown compound with a mass of 2.876 g has 66.07 percent carbon, 6.71 percent hydrogen, 4.06 percent nitrogen and 23.16 percent oxygen. What is the mass of each element in this compound?
5. Find the percent composition of a compound that contains 2.7369 g of chlorine, 0.4116 g of oxygen and 0.7971 g of phosphorus.
6. Find the percent composition of a compound that contains 1.51 g of chromium, 1.13 g of potassium and 1.62 g of oxygen.
7. A sample of a compound with a mass of 0.432 g is analyzed. The sample is found to contain only fluorine and oxygen. If the compound contains 0.128 g oxygen, calculate the percent composition of the compound.
page 13
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Empirical Formulas 1. Determine the empirical formula of a compound containing 2.644 g of gold and 0.476 g chlorine.
2. Determine the empirical formula of a compound containing 0.928 g of gallium and 0.412 g phosphorus.
3. Determine the empirical formula of a compound containing 47.9% zinc and 52.1% chlorine by mass.
4. Determine the empirical formula of a compound containing 1.75 g of carbon and 46.75 g bromine.
5. Determine the empirical formula of a compound containing 20.23% aluminum and 79.77% chlorine by mass.
page 14
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6. Determine the empirical formula of a compound containing 4.288 g of carbon and 5.712 g oxygen.
7. Determine the empirical formula of a compound containing 3.611 g of calcium and 6.389 g chlorine.
8. Determine the empirical formula of a compound containing 1.723 g of carbon, 0.289 g of hydrogen and 0.459 g oxygen.
9. Determine the empirical formula of a compound containing 24.74% potassium, 34.76% manganese and 40.50% oxygen by mass.
10. Determine the empirical formula of a compound containing 2.16 g of aluminum, 3.85 g of sulfur and 7.68 g oxygen.
page 15
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Molecular Formulas 1. Determine the molecular formula of a compound containing 42.56 g of palladium and 0.80 g of hydrogen. The molar mass of the compound is 216.8 g/mol.
2. Determine the molecular formula of a compound that is 30.45% nitrogen and 69.55% oxygen. The molar mass of the compound is 92 g/mol.
3. Determine the molecular formula of a compound containing 42.4 g of hydrogen and 169.7 g of carbon. The molar mass of the compound is 30.0 g/mol.
page 16
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4. Determine the molecular formula of a compound containing only boron and iodine if in a 310.8 g sample, the mass of the iodine is found to be 302.2 g. The molar mass of the compound is 391.5 g/mol.
5. Determine the molecular formula of a compound containing 56.36 g of oxygen and 43.64 g of phosphorus. The molar mass of the compound is 283.9 g/mol.
page 17
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Hydrates 1. Find the empirical formula of the hydrate given that it is 27.76% manganese, 35.83% chlorine and 36.40% water.
2. Two hydrates of cobalt(II) chloride exist. One is 21.68% water the other is 45.43% water. What are their empirical formulas?
page 18
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Challenge Problems – The Mole 1. How many molecules are in a sample of water that requires 8.40 kcal of heat energy to raise the temperature by 34.0°C?
2. A compound of hydrogen and carbon has a molar mass 114 g/mol. If one mole of the compound contains 18.02 g of hydrogen, what is the compound’s molecular formula?
5
3. How many atoms of iron are in a cube of iron that is 1.00 x 10 µm on a side? Use a reference source to find the density of iron.
page 19
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4. A mixture of salt and pepper analyses to be 50% chlorine by mass. If pepper contains no chlorine, what percent of the mixture is pepper?
5. A solution is made that is 2.00 M for aluminum nitrate. What volume of this solution contains 0.250 moles of nitrate ions?
page 20
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6. A solution of ammonium sulfate is made that is 2.25 M for ammonium ions. What volume of this solution can be produced using only 50.0 g of ammonium sulfate?
23
7. A sample of hydrated sodium salt gives off 2.02 x 10 molec. of water when it is heated. When the dehydrated sample is analyzed it is found to contain 1.285 g sodium, 0.865 g phosphorus, 0.3136 L hydrogen gas and 1.25 L of oxygen gas at STP. Calculate the empirical formula of the hydrate.
page 21
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Mole Word Scramble Use the clues provided to help you unscramble the letter to form words related to the mole. The letters in the circle spell out, in order, the name of a famous chemist. CLUES 1. 1/12 of a Carbon-12 atom 2. Mass of one object compared to that of another object 23
3. 6.02 x 10
of anything
4. Method for solving a problem 5. Found by adding the atomic masses of all the elements in the molecule 6. Means that there are two atoms in a molecule 7. Formula representing the smallest whole-number ratio of atoms in a compound 8. Number of moles of dissolved substance per liter of solution 1. S A N I O M S M T T U A C I
__ __ __ __ __ __ __ __ __ __ __ __ __ __
2. V E T S A M S I R E L A
__ __ __ __ __ __ __ __ __ __ __ __
3. L O E M
__ __ __ __
4. M A H L T G I O R
__ __ __ __ __ __ __ __ __
5. R A L S U C E S A M L O M
__ __ __ __ __ __ __ __ __ __ __ __ __
6. T A D I M O C I
__ __ __ __ __ __ __ __
7. I M P E C I L A R
__ __ __ __ __ __ __ __ __
8. R I L Y T A O M
__ __ __ __ __ __ __ __
NAME: ____________________________
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