Page 1280 - Chemistry--atom first

1270 Answer Key
(c) These molecules have the same chemical composition (types and number of atoms) but different chemical structures. They are structural isomers.
37. 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.
39. 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.
41. 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.
43. (a) 256.528 g/mol; (b) 72.150 g mol−1; (c) 378.103 g mol−1; (d) 58.080 g mol−1; (e) 180.158 g mol−1 45. (a) 197.382 g mol−1; (b) 257.163 g mol−1; (c) 194.193 g mol−1; (d) 60.056 g mol−1; (e) 306.464 g mol−1
47. (a) 0.819 g;
(b) 307 g;
(c) 0.23 g;
(d) 1.235 106 g (1235 kg); (e) 765 g
49. (a) 99.41 g; (b) 2.27 g;
(c) 3.5 g;
(d) 222 kg;
(e) 160.1 g
51. (a) 9.60 g; (b) 19.2 g; (c) 28.8 g
53. zirconium: 2.038 1023 atoms; 30.87 g; silicon: 2.038 1023 atoms; 9.504 g; oxygen: 8.151 1023 atoms; 21.66 g
55. AlPO4: 1.000 mol Al2Cl6: 1.994 mol Al2S3: 3.00 mol
57. 3.113 1025 C atoms
59. 0.865 servings, or about 1 serving.
61. 20.0 g H2O represents the least number of molecules since it has the least number of moles.
Chapter 3
1. The spectrum consists of colored lines, at least one of which (probably the brightest) is red.
3. 3.15 m
5. 3.233 10−19 J; 2.018 eV
7.ν = 4.568 1014 s; λ = 656.3 nm; Energy mol−1 = 1.823 105 J mol−1; red
9. (a) λ = 8.69 10−7 m; E = 2.29 10−19 J; (b) λ = 4.59 10−7 m; E = 4.33 10−19 J; The color of (a) is red; (b) is blue.
11. E = 9.502 10−15 J; ν = 1.434 1019 s−1
13. Red: 660 nm; 4.54 1014 Hz; 3.01 10−19 J. Green: 520 nm; 5.77 1014 Hz; 3.82 10−19 J. Blue: 440 nm;
6.81 1014 Hz; 4.51 10−19 J. Somewhat different numbers are also possible.
15. 5.49 1014 s−1; no
17. Quantized energy means that the electrons can possess only certain discrete energy values; values between those
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