Chapter 8 Review
Vocabulary
10. An ionic formula is always an ________.
Match each word to the sentence where it best
fits.
11. Some ________ are natural and are necessary for
correct biological functioning, while others are
sometimes taken as drugs.
Section 8.1
12. Some of the highest calorie foods contain
________.
brittle
polyatomic ion
electric current
1. Something that is ________ can be strong but still
break easily.
2. If you have a ________ you have a small molecule
with a charge.
3. When charge moves in a directed way you have an
________.
Section 8.2
lipids
copolymers
steroids
network covalent
hydrocarbon
empirical formula
polymers
molecular formula
monomer
organic molecule
homopolymer
4. A ________ will tell you exactly how many atoms
there are in an individual molecule.
5. Most of our fuels are one kind of ________ or
another, because the carbon and hydrogen they
contain have a large amount of chemical energy.
6. Molecules that are made from repeatedly bonding
together smaller molecules are broadly called
________.
7. ________ are bonded together to form polymers.
13. Protein and DNA are molecules that are examples
of ________.
14. The type of molecular substances that form very
large interconnected molecules are called
________.
Section 8.3
intermolecular
attractions
hydrogen bonding
van der Waals
attractions
London dispersion
attraction
surface tension
dipole-dipole
attraction
15. ________ is a slightly stronger version of dipoledipole attraction, but it is not as strong as a
covalent bond.
16. Two broad terms that describe why molecules
condense into liquids and solids are ________ and
________.
17. When two polar molecules attract to each other
you have an example of ________.
18. You can “float” a paper clip on water if you very
carefully lay it flat on top of the water. This is due
to what is known as ________.
19. ________ is particularly important for non-polar
molecules.
8. Polypropylene is only made from one monomer,
so it is a ________.
Conceptual Questions
9. For a molecule to be an ________ it must be made
primarily from carbon and hydrogen with the
possibility of some other non-metals also part of
the molecule.
Section 8.1
256
20. What is one property shared by most ionic
substances?
A NATURAL APPROACH TO CHEMISTRY
21. Why do ionic substances not conduct electricity in
their solid form, but will if they are dissolved or in
their liquid form?
37. Which kinds of molecular substances most
resemble ionic compounds and in what ways are
they similar?
22. True or false. The positive ion in an ionic
compound must have the same charge as the
negative ion. Explain.
38. Describe the difference between an empirical
formula and a molecular formula.
23. Describe the structure of an ionic crystal.
Section 8.3
24. In what ways is an ionic crystal like a molecule
and in what ways is it different?
39. What are the major categories of intermolecular
attractions?
25. Describe why you sometimes need parentheses
around a polyatomic ion when used in a formula.
Give one example of when you need parentheses
and one where you don’t.
40. Is a hydrogen bond more like a dipole-dipole
attraction or more like a London dispersion
attraction? Explain.
26. Why must the total positive and total negative
charge in an ionic compound be equal?
27. Why do some ionic names need a Roman numeral,
and some don’t. Give an example.
Section 8.2
28. Describe a major difference between the
properties of ionic compounds and molecular
compounds.
41. Dipole-dipole attractions occur between which
types of molecules:
a. network covalent
b. polar
c. non-polar
42. Explain why water has a boiling point that is so
much higher than most molecules that are so
small.
43. List three special properties of water, not
including its high boiling point.
29. What are some common properties of substances
made from small molecules?
44. Describe the difference between London
dispersion attraction and dipole-dipole attraction.
30. If two small molecules are about the same size,
but one is polar, which one will have the higher
boiling point?
45. How does the size of a molecule play a role in the
strength of its intermolecular attractions?
31. Gasoline is a hydrocarbon. What does that mean?
46. How does the shape of a molecule play a role in
the strength of its intermolecular attractions?
32. What is a common property of substances made
from medium-sized molecules?
47. How does the polarity of a molecule play a role in
the strength of its intermolecular attractions?
33. If you wanted to avoid lipids, what foods should
you not eat?
Section 8.4
34. Describe the relationship between a monomer and
a polymer.
48. What does an empirical formula tell you? Give an
example.
35. How many different monomers are used to make
proteins?
49. Give an example of when a molecular formula is
the same as its empirical formula.
36. What do we call a monomer that is used to make a
protein?
50. Give an example when the molecular formula is
different from the empirical formula.
A NATURAL APPROACH TO CHEMISTRY
257
Chapter 8 Review.
51. Describe how the percent composition helps in
determining the molecular formula of an unknown
substance.
Quantitative Problems
Section 8.1
52. What does the formula BaCl2 tell you about the
substance barium chloride?
53. Write the formula for each of the following names:
a. lithium bromide
b. magnesium fluoride
c. calcium sulfide
d. aluminum iodide
e. aluminum sulfide
54. Write the formula for each of the following names:
f. chromium(III) nitrate
g. copper(I) oxide
h. copper(II) oxide
i. lithium phosphate
j. iron(III) sulfate
55. Write the formula for each of the following names:
a. barium hydroxide
b. sodium sulfide
c. tin(IV) carbonate
d. cobalt(II) chlorate
56. Write the name for each of the following formulas:
a. K2O
b. BeI2
c. SrCl2
d. PbCl4
57. Write the name for each of the following formulas:
258
a.
b.
c.
d.
e.
FeO
Fe2O3
ZnBr2
AgNO3
K2CO3
58. Write the name for each of the following formulas:
a. NaHCO3
b. Sn(NO3)2
c. (NH4)2SO4
d. Al(C2H3O2)3
e. CuSO4
Section 8.2
59. Write the formula for each of the following names:
a. dinitrogen monoxide
b. dichlorine hexoxide
c. iodine tribromide
60. Write the formula for each of the following names
a. iodine heptafluoride
b. phosphorous trichloride
c. chlorine monoiodide
d. dinitrogen tetrafluoride
61. Write the names for each of the following
formulas:
a. SF2
b. P4O10
c. P2Cl4
62. Write the names for each of the following
formulas:
d. Cl2O7
e. PF5
f. S2F10
A NATURAL APPROACH TO CHEMISTRY
Section 8.3
68. Calculate how many molecules are in the
following
a. 6.5 g of H2O
b. 19.3 g of C8H10
69. Give the empirical formula for each of the
molecular formulas:
a. N2O4
b. P2O5
c. P4H10
d. H2O2
e. P3Cl5
70. Give three possible molecular formulas for the
empirical formula CH2O.
71. If you had a sample of a substance that had 20.23g
of aluminum and 79.77g of chlorine, what would
the empirical formula be for this substance?
63. There are four DNA bases that are part of the
nucleotide monomers that make up the DNA
molecule. When two DNA strands wrap around
each other they only stick together if there is an
“A” on one strand across from a “T” on the other
or a “G” on one strand across from a “C” on the
other. Which pair do you think sticks together
better and why?
64. Why does it make sense that “A” and “T” pair up
and “G” and “C” pair up?
Section 8.4
65. Calculate the molar mass for the following
substances:
a. H2O
b. NaNO3
c. (NH4)2S
d. Ca3(PO4)2
66. What is the percent composition by mass for each
of the substances in the previous question?
67. If you add up all the % of each element in a
compound you should get what number?
A NATURAL APPROACH TO CHEMISTRY
72. What is the empirical formula for a substance with
the following % composition:
40% carbon
6.7% hydrogen
53.3% oxygen
73. You have 16.0g of some compound and you
perform an experiment to remove all of the
oxygen. What is left is 11.2g of iron. What is the
empirical formula?
74. After burning 1.5g of scandium in oxygen, a new
compound is formed that has a mass of 3.1g. What
is the empirical formula.
75. The empirical formula for cyclohexane is CH2,
and its molar mass is 84.18g/mol. What is the
molecular formula?
76. What is the molecular formula for a compound
with a molar mass of 34.02g/mol and empirical
formula HO?
77. A sample of an unknown compound was
determined to be made from 8.56g of carbon and
1.44g of hydrogen. The molar mass of the
compound was found to be 28.03g/mol. What is
the molecular formula?
259