Chem 1721/1821
Name ___________________________________
Quiz 2 (20 points)
1.
February 6, 2013
NA = 6.022 x 1023 mol−1
C = kP
A covalent-network solid is most likely to be
a. soft with a high melting point, and a good conductor
b. hard with a high melting point, and not a conductor
c. soft with a low melting point, and not a conductor
d. hard with a low melting point, and a good conductor
e. none of these
2.
3.
A scientist examines a sample of an unknown solid and determines that it is brittle, has a high melting point, and while it
does not conduct electricity in the solid state, it is conductive in its molten form. This solid should be classified as a(n)
a. molecular solid
b. covalent-network solid
d. metallic solid
e. none of these
c. ionic solid
Consider the following ionic compounds: BaO, MgO, CsI, and BaS. Which one of these would you predict has the
highest melting point?
4.
_______________________
Palladium crystallizes with the unit cell shown to the right. The length of the unit cell
edge for palladium is 388.8 pm. Determine (a) the atomic radius (in pm) of palladium,
and (b) the density (in g/cm3) of palladium.
b. d = _______________________ g/cm3
a. r = ________________________ pm
5.
Consider the compounds labeled A, B, and C shown below, then answer the questions that follow.
O
H2
C
H3C
H2
C
C
H2
C
H2
A
6.
C
OH
H3C
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
B
O
C
H2
C
OH
H2
C
HO
C
H2
OH
C
a.
Which one of these {A, B, or C} should be the most hydrophobic?
_____________
b.
Which one of these {A, B, or C} would you predict is miscible with water?
_____________
For carbon monoxide in water at 25oC, the Henry’s law constant, k = 9.5 x 10−4 mol/Latm. Determine the partial
pressure of carbon monoxide required (in atm) to reach a CO concentration of 0.0831 mol/L.
______________________
7.
A metal in its pure (elemental) form crystallizes in one of the structures that we have discussed. Which one of the
following cubic unit cells would be consistent with this metal having the smallest density?
a. simple cubic unit cell
b. face-centered cubic unit cell
c. body-centered cubic unit cell
d. face-centered cubic and body-centered cubic would result in the same density
e. simple cubic and body-centered cubic would result in the same density
f. cannot answer without knowing the identity of the metal
8.
Consider the unit cells shown below, then answer the questions that follow.
A
B
a.
A particle on a face of unit cell A is shared between how many different unit cells?
______________
b.
Which one of these unit cells {A, B, or C} represents a structure with a close-packed lattice?
______________
c.
What is the total number of particles in unit cell C?
______________
d.
Which one of these unit cells {A, B, or C} represents a lattice in which all layers are stacked directly on top of one
another?
9..
C
______________
12.50 g diethyl ether (C4H10O, molar mass = 74.12 g/mol, d = 0.7134 g/mL) is dissolved in 87.50 g cyclohexanol
(C6H12O, molar mass = 100.2 g/mol, d = 0.9620 g/mL).
a.
Determine the mass percent cyclohexanol in this solution.
_________________________
b.
Determine the amount (in mol) of solute in this solution.
_________________________
c.
Determine the molality of this solution.
_________________________
d.
Determine the total volume of this solution.
_________________________
e.
Determine the molar concentration of this solution.
_________________________
Chem 1721/1821
Name ___________________________________
Quiz 2 (20 points)
1.
February 6, 2013
C = kP
NA = 6.022 x 1023 mol−1
A metal in its pure (elemental) form crystallizes in one of the structures that we have discussed. Which one of the
following cubic unit cells would be consistent with this metal having the greatest density?
a. body-centered cubic unit cell
b. simple cubic unit cell
c. face-centered cubic unit cell
d. face-centered cubic and body-centered cubic would result in the same density
e. simple cubic and body-centered cubic would result in the same density
f. cannot answer without knowing the identity of the metal
2.
Consider the unit cells shown below, then answer the questions that follow.
A
4..
C
a.
What is the total number of particles in unit cell A?
______________
b.
A particle in the center of unit cell C is shared between how many different unit cells?
______________
c.
Which one of these unit cells {A, B, or C} represents a lattice in which all layers are stacked directly on top of one
d.
3.
B
another?
______________
Which one of these unit cells {A, B, or C} represents a structure with a close-packed lattice?
______________
A scientist examines a sample of an unknown solid and determines that it is brittle, has a high melting point, and while it
does not conduct electricity in the solid state, it is conductive in its molten form. This solid should be classified as a(n)
a. ionic solid
b. metallic solid
d. covalent-network solid
e. none of these
c. molecular solid
22.50 g diethyl ether (C4H10O, molar mass = 74.12 g/mol, d = 0.7134 g/mL) is dissolved in 77.50 g cyclohexanol
(C6H12O, molar mass = 100.2 g/mol, d = 0.9620 g/mL).
a. Determine the mass percent cyclohexanol in this solution.
_________________________
b.
Determine the amount (in mol) of solute in this solution.
_________________________
c.
Determine the molality of this solution.
_________________________
d.
Determine the total volume of this solution.
_________________________
e.
Determine the molar concentration of this solution.
_________________________
5.
A covalent-network solid is most likely to be
a. hard with a high melting point, and not a conductor
b. soft with a high melting point, and a good conductor
c. hard with a low melting point, and a good conductor
d. soft with a low melting point, and not a conductor
e. none of these
6.
For carbon monoxide in water at 25oC, the Henry’s law constant, k = 9.5 x 10−4 mol/Latm. Determine the partial
pressure of carbon monoxide required (in atm) to reach a CO concentration of 0.0831 mol/L.
______________________
7.
Consider the compounds labeled A, B, and C shown below, then answer the questions that follow.
O
H2
C
H3C
H2
C
C
H2
C
C
H2
OH
H3C
A
8.
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
C
H2
H2
C
O
C
H2
C
OH
C
H2
OH
C
B
a.
Which one of these {A, B, or C} would you predict is miscible with water?
_____________
b.
Which one of these {A, B, or C} should be the most hydrophobic?
_____________
Consider the following ionic compounds: BaO, MgO, CsI, and BaS. Which one of these would you predict has the
lowest melting point?
9.
H2
C
HO
_______________________
Palladium crystallizes with the unit cell shown to the right. The length of the unit cell
edge for palladium is 388.8 pm. Determine (a) the atomic radius (in pm) of palladium,
and (b) the density (in g/cm3) of palladium.
a. r = ________________________ pm
b. d = _______________________ g/cm3