3.1 Formula Mass and the Mole Concept |
1. |
(a) |
12.01 amu |
|
(b) |
12.01 amu |
|
(c) |
144.12 amu |
|
(d) |
60.05 amu |
3. |
(a) |
123.896 amu |
|
(b) |
18.015 amu |
|
(c) |
164.086 amu |
|
(d) |
60.052 amu |
|
(e) |
342.297 amu |
5. |
(a) |
56.107 amu |
|
(b) |
54.091 amu |
|
(c) |
199.9976 amu |
|
(d) |
97.9950 amu |
7. |
Use the molecular formula to find the molar mass; to obtain the number of moles, divide the mass of compound by the molar mass of the compound expressed in grams. |
9. |
Formic acid. Its formula has twice as many oxygen atoms as the other two compounds (one each). Therefore, 0.60 mol of formic acid would be equivalent to 1.20 mol of a compound containing a single oxygen atom. |
11. |
The two masses have the same numerical value, but the units are different: The molecular mass is the mass of 1 molecule while the molar mass is the mass of 6.022 × 1023 molecules. |
13. |
(a) |
256.48 g/mol |
|
(b) |
72.150 g/mol |
|
(c) |
378.103 g/mol |
|
(d) |
58.080 g/mol |
|
(e) |
180.158 g/mol |
15. |
(a) |
197.382 g/mol |
|
(b) |
257.163 g/mol |
|
(c) |
194.193 g/mol |
|
(d) |
60.056 g/mol |
|
(e) |
306.464 g/mol |
17. |
(a) |
0.819 g |
|
(b) |
307 g |
|
(c) |
0.23 g |
|
(d) |
1.235 x 106 g (1235 kg) |
|
(e) |
765 g |
19. |
(a) |
99.41 g |
|
(b) |
2.27 g |
|
(c) |
3.5 g |
|
(d) |
222 kg |
|
(e) |
160.1 g |
21. |
(a) |
9.60 g |
|
(b) |
19.2 g |
|
(c) |
28.8 g |
23. |
zirconium: 2.0381023 atoms, 30.87 g; silicon: 2.038 x 1023 atoms, 9.504 g; oxygen: 8.151 × 1023 atoms, 21.66 g |
25. |
AlPO4: 1.000 mol, or 26.98 g Al; Al2Cl6: 1.994 mol, or 53.74 g Al; Al2S3: 3.00 mol, or 80.94 g Al; The Al2S3 sample thus contains the greatest mass of Al. |
27. |
3.113 x 1025 C atoms |
29. |
0.865 servings, or about 1 serving. |
31. |
20.0 g H2O represents the least number of molecules since it has the least number of moles. |