Download Atoms, Molecules, and Ions

CHHS Advanced Placement Chemistry, 2007
Ponzell S. Goff
Atoms, Molecules, and Ions
(Hill, Pettrucci 4th edition, Ch. 2)
Vocabulary
1. Law of Conservation of Mass
3. Law of Multiple Proportions
5. Isotopes
7. Nonmetals
9. Chemical formula
11. Molecular compound
13. Molecular formula
15. Ions
17. Cations
19. Formula units
21. Hydrates
23. Bases
25. Hydrocarbons
27. Isomers
29. Alcohols
2. Law of Constant Composition
4. Dalton’s Atomic Theory
6. Mendeleev’s Periodic Table
8. Metalloids
10. molecule
12. Empirical formula
14. Structural formula
16. Anions
18. Monatomic ions
20. Polyatomic ions
22. Acids
24. Salt
26. Alkanes
28. Alkyl groups
30. Carboxylic acids
Example 2.1 a). A sealed photographic flashbulb containing magnesium and
oxygen has a mass of 45.07 g. On firing, a brilliant flash of white light is emitted
and a white powder is formed inside the bulb. What should the mass of the bulb
be after firing? Explain.
2.1b) Is the mass of a burned match the same as, less than, or more than the mass
of a burning mass? Explain your answer.
Example 2.2 The mass ratio of oxygen to magnesium in the compound
magnesium oxide is 0.6583: 1. What mass of magnesium oxide will form when
2.000 g of magnesium is completely converted to magnesium oxide by burning in
pure oxygen gas?
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CHHS Advanced Placement Chemistry, 2007
Ponzell S. Goff
2.2 a) What mass of magnesium oxide is formed when 1.500 g of oxygen
combines with magnesium?
2.2 b) When a strip of magnesium metal was burned in pure oxygen gas, 1.554
g of oxygen was consumed and the only product formed was magnesium oxide.
What must have been the masses of magnesium metal burned and magnesium
oxide formed?
Example 2.3a How many protons, neutrons, and electrons are in a 81Br atom?
2.2a Use the notation AZE to represent the isotope of tin having 66 neutrons.
Example 2.4
Isotope
Percent Abundance
Fractional Abundance
Carbon-12 98.892%
0.98892
Carbon-13 1.108%
0.01108
Use the data cited above to determine the weighted average atomic mass of
carbon.
2.4a) There are three naturally occurring isotopes of neon. Their percent
abundances and atomic masses are neon-20, 90.15%, 19.99244 u; neon-21, 0.27%,
20.99395 u: neon-22, 9.22%, 21.99138 u. Calculate the weighted average atomic
mass of neon.
Example 2.5 Indium has 2 naturally occurring isotopes and a weighted average
atomic mass of 114.82 u. One of the isotopes has a mass of 112.9043 u. This is
likely to be the second isotope: 111In, 112In, 114In, or 115In
Example 2.6 Write the molecular formula and name of a compound for which
each molecule contains six oxygen atoms and four phosphorus atoms.
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CHHS Advanced Placement Chemistry, 2007
Ponzell S. Goff
Example 2.6a Write the molecular formula and name of a compound for which
each molecule contains four fluorine and two nitrogen atoms.
Example 2.7 Write (a) the molecular formula of phosphorus pentachloride and
(b) the name of S2F10.
2.7a Write (a) the molecular formula of tetraphosphorus decoxide and (b) the
name of S7O2.
Example 2.8 Determine the formula for (a) calcium chloride and (b) magnesium
oxide.
Example 2.8a Give the formula for each of the following ionic compounds.
(a) potassium sulfide
(b) lithium oxide
(c) aluminum fluoride
Example 2.8b Give the formula for each of the following ionic compounds:
(a) chromium (III) oxide
(b) iron (II) sulfide
(c) lithium nitride
Example 2.9 What are the names of:
(a) MgS
(b) CrCl3?
2.9a Write the name and formula for each of the following compounds:
(a) the sulfide of copper (I)
b) the oxide of cobalt (III)
(c) the nitride of magnesium
Example 2.10 Write the formula for (a) sodium sulfite and (b) ammonium sulfate
2.10a What is the formula for (a) ammonium carbonate, (b) calcium
hypochlorite, and (c) chromium (III) sulfate?
2.10ab Write a plausible formula for (a) potassium aluminum sulfate
(b) magnesium ammonium phosphate
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CHHS Advanced Placement Chemistry, 2007
Ponzell S. Goff
Example 2.11 What is the name of (a) NaCN and (b) Mg (ClO4)2?
Example 2.11a Name each of the following compounds:
(a) KHCO3
(b) FePO4
(c) Mg(H2PO4)
Example 2.11b Give a plausible name for the following:
(a) Na2SeO4
(b) FeAs
(c) Na2HPO3
Cumulative Example
Show that the following experiment is consistent with the Law of Conservation
of Mass (within the limits of experimental error): A 10.00-g sample of calcium
carbonate was dissolved in 100.0 mL of hydrochloric acid solution (d = 1.148
g/mL). The products were 120.40 g of solution (a mixture of hydrochloric acid
and calcium chloride ) and 2.22 L of carbon dioxide gas (d = 0.0019769 g/mL).
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