43) Which of the following can be called a non-molecular ionic solid?
A) water
B) sodium chloride
C) methane
D) hydrogen
44) Which of the following may not be considered an ionic compound?
A) sodium chloride
B) magnesium oxide
C) ammonia
D) potassium bromide
45) Which statement is true about network solids?
A) They have extremely high melting points.
B) They are covalent substances.
C) They are large network molecules held by covalent compounds.
D) All of the above are true.
46) Which of these has the highest melting point?
A) diamond
B) iron
C) sodium
D) bromine
7.2 True/False Questions
1) The melting and freezing points are identical for the same compound.
2) At the freezing point the molecules are effectively frozen in place.
3) Solid carbon dioxide is also known as dry ice.
4) The freezing point of dry ice is 0 °C.
5) The attractive forces between carbon dioxide molecules are considerably stronger than those
found in water molecules.
6) The terms “dispersion forces” and “London forces” are interchangeable.
7) Polar molecules do not exhibit London forces.
8) London forces become significant for large molecules with many atoms and many electrons.
9) The acetone molecule has a large dipole because of the electronegativity difference between
carbon and oxygen.
10) Water has a much higher boiling point than acetone due to the ability of water to undergo
hydrogen bonding.
11) Vancomycin is the first line of defense against bacteria.
12) The replacement of a single NH group on vancomycin causes the antibiotic to become
ineffective.
13) Quartz contains atoms that are held together with hydrogen bonding.
14) Molecular substances have a higher melting point than non-molecular substances
15) Quartz and diamond are non-molecular solids, where the atoms are held together with
covalent bonds.
7.3 Short Answer Questions
Identify the following crystalline solids as ionic, molecular, or metallic.
1) calcium chloride, CaC12
2) glucose, C6H12O6
3) chromium, Cr
4) iodine, I2
5) copper (II) carbonate, CuCO3 (or cupric carbonate)
Based upon the formulas and melting points, decide whether each of the following crystalline
substances should be classified as an ionic solid, a molecular solid, a metal or a network solid.
6) magnesium chloride, MgC12, m.p.: 714 °C
7) niobium, Nb, m.p.: 2468 °C
8) silicon carbide, SiC, m.p.: 2700 °C
9) ethanol, C2H6O, m.p.: -117 °C
10) sodium fluoride, NaF, m.p.: 993 °C
11) What is the general trend in terms of increasing melting point for ionic solids, molecular
solids, and network covalent solids?
17
7.4 Matching Questions
Identify each of the compounds in the left column as molecular or non-molecular.
A) non-molecular
B) molecular
1) water
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
2) sodium oxide
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
3) graphite
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
4) ammonia
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
5) sodium chloride
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
6) methane
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
7) hydrogen
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
8) silicon dioxide
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
9) carbon tetrachloride
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
10) aluminum oxide
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
11) copper
Section: Section 7.4
Learning Outcome: 7.6 Describe what a nonmolecular substance is on an atomic level.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
Match the description of processes that appear in the left column with the corresponding change
of states on the right column.
A) sublimation
B) evaporation
C) melting
D) condensation
E) freezing
12) liquefaction of butter on hot bread
Section: Section 7.1
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
13) “disappearance” of mothballs
Section: Section 7.1
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
14) water boiling
Section: Section 7.1
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
15) ice formation on a pond during winter
Section: Section 7.1
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
16) collection of water droplets on the medicine cabinet mirror during a prolonged hot shower
Section: Section 7.1
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
Match the temperatures in the left column with the processes described in the right column.
A) boiling point of ethanol
B) boiling point of nitrogen
C) deposition point of carbon dioxide
D) boiling point of water
E) melting point of water
F) boiling point of hydrogen
17) -253 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
18) -196 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
19) -78 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
20) 0 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
21) 78 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
22) 100 °C
Section: Section 7.2
Learning Outcome: 7.2 Explain what is necessary for one phase to transform into another.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
21
Match each of the substances in the left column with the STRONGEST type of bonding that it
exhibits.
A) hydrogen bonding
B) London forces
C) network covalent bonding
D) metallic
23) water
Section: Section 7.3
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
24) carbon tetrabromide
Section: Section 7.2
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
25) iron
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
26) hydrogen fluoride
Section: Section 7.3
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
27) carbon tetrachloride
Section: Section 7.2
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
28) quartz
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
29) ammonia
Section: Section 7.3
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
30) diamond
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
31) graphite
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
32) boron trifluoride
Section: Section 7.2
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
33) titanium
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
34) methane
Section: Section 7.2
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.
35) sodium
Section: Section 7.4
Learning Outcome: 7.5 Predict the most important intermolecular force present and its effect on
physical properties.
Global Obj: G2 Demonstrate the ability to think critically and employ critical thinking skills.