Answer Key
Chapter 10
Practice Problems
1. 9.451024 molecules CO2
2. 3.271022 molecules H2O
3. 1.53 mol Fe
4. 0.0341 mol sucrose
5. 1.081021 formula units
CuSO4
6. 839 g Sb
7. 5.53 g Se
8. 6.95 mol S
9. 12.5 mol He
10. 0.0213 mol Ni
11. 6.171021 atoms Pt
12. 1.881028 atoms S
13. 39.7 g Hg
14. 6.35103 g
15. 4.361016 Pb ions
16. 0.220 mol C6H6
17. 2.856 mol KClO3
18. 40.2 g SnSO4
19. 3.40102 g (340 g expressed
to 3 significant figures)
20. 13.1 g Zn and 37.5 g
Cu(NO3)2
21. 52.93% Al, 47.07% O
22. 16.39% Mg, 18.89% N,
64.72% O
23. 39.17% O
24. 49.30% N
25. The percent compositions
will be the same because the
ratio of carbon atoms to
hydrogen atoms is the same,
1:1.
26. CH2O
27. ZnN2O6
28. Al4C3
29. C3H4O3
30. C8H8N2O2
31. B3H6N3
32. Ag2C2O4
33. P2S5; same as empirical
formula
34. C9H12N6
35. CeI39H2O
36. Co(NO3)26H2O
37. Pb(C2H3O2)23H2O
38. ZnSO47H2O
Chemistry: Matter and Change Solving Problems:1A Chemistry Handbook
Answer Key (continued)
Chapter 10 Review
39. One mole of a substance consists of 6.021023 particles of that
substance. The mass in grams of a mole of a substance is
numerically equal to the sum of the atomic masses of the atoms that
make up the particles of that substance.
40. The quantities of reactants and products in a chemical equation are
given as numbers of particles or moles of particles, not as masses.
41. The molar mass of a compound in grams is numerically equal to the
sum of the atomic masses of the atoms in a representative particle of
the compound.
42. 28.014 g, which is twice the atomic mass expressed in grams
43. Yes; you would expect the compositions to be the same. A
compound is a substance, and the law of definite proportions states
that the composition of a substance is the same wherever the
substance is found.
44. The molecular formula will be a whole-number multiple of the
empirical formula but could also be the same as the empirical
formula.
45. The six water molecules are incorporated in the crystal structure but
are separate from the compound. The formula with water molecules
shown separately better represents the composition of the
compound.
Chemistry: Matter and Change
Solving16Problems: A Chemistry Handbook