CHAPTER
Liquids and Solids
11
Section 11.1 Properties of Liquids
2.
4.
General Observed Properties of Liquids
True, liquids have a fixed volume.
True, liquids that are soluble mix homogeneously with each other.
False, liquids do not expand significantly with changes in temperature
or pressure; however, they may undergo a change in physical state.
(d) False, liquids are about 1000 times more dense than gases.
(a)
(b)
(c)
Substance
(a) H2 O
(b) H2 O
(c) NH3
(d) NH3
(e) CHCl3
(f) CHCl3
Temperature
–10 °C
110 °C
–100 °C
–50 °C
100 °C
50 °C
Physical State
solid
gas
solid
liquid
gas
liquid
Section 11.2 The Intermolecular Bond Concept
6.
A hydrogen bond is a specific example of permanent dipole attraction between
molecules. A permanent dipole is caused by electrons being drawn closer to one
atom than another within a molecule. If a molecule has an O–H bond such as
H2 O, or an N–H bond such as NH3 , a hydrogen bond results between the H
atom and the O or N atom on another molecule.
Section 11.3 Vapor Pressure, Boiling Point, Viscosity, Surface Tension
8.
The boiling point of water occurs when the total pressure exerted by the water
molecules in the gaseous state above the liquid equals the pressure exerted by
the atmosphere.
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10.
A water molecule at the surface of the liquid is attracted to adjacent molecules.
This attraction, called surface tension, causes a drop of water to have the smallest
possible surface area, and thus assumes a spherical shape.
12.
If the molecules in a liquid are strongly attracted:
(a) the vapor pressure is low.
(b) the boiling point is high.
(c) the viscosity is high.
(d) the surface tension is high.
14.
16.
18.
20.
22.
(a)
(b)
Liquid
CH3 COOH or C2 H5 Cl
C 2 H5 OH or CH3 OCH3
Higher Boiling Point
CH3 COOH (stronger attraction)
C 2 H5 OH (stronger attraction)
(a)
(b)
Liquid
CH3 COOH or C2 H5 Cl
C 2 H5 OH or CH3 OCH3
Higher Surface Tension
CH3 COOH (stronger attraction)
C 2 H5 OH (stronger attraction)
When the vapor pressure of the liquid is equal to the atmospheric pressure, the
liquid begins to boil.
(a)
(b)
Temperature
15 °C
30 °C
Vapor Pressure
~70 mmHg
~300 mmHg
The temperature at which the vapor pressure of a liquid is equal to the
atmospheric pressure is the boiling point. Thus, the boiling point of methanol is
65 °C because its vapor pressure at this temperature is 1 atm.
Section 11.4 Properties of Solids
24.
26.
(a)
(b)
(c)
(d)
General Observed Properties of Solids
True, solids have a fixed volume.
True, solids can have a noncrystalline structure.
True, solids do not expand significantly.
False, alloys mix in the liquid state and cool to a solid.
(a)
(b)
Substance
Hg
Hg
Temperature
ice water, 0 °C
boiling water, 100 °C
Physical State
liquid
liquid
Section 11.5 Crystalline Solids
28.
80
Most solids are noncrystalline heterogeneous mixtures. For example, rocks,
wood, concrete, and most naturally occurring minerals are noncrystalline.
Chapter 11
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30.
32.
(a)
(b)
(c)
Properties
malleable, ductile, conductor
high melting point, conductor
low melting point, nonconductor
Type of Solid
metallic solid
ionic solid
molecular solid
Crystalline Solid
(a) S8
(b) SO2
(c) Cu
(d) AgNO3
Classification
molecular solid
molecular solid
metallic solid
ionic solid
Section 11.6 Changes of Physical State
34.
Cooling Curve for Acetone
—Gas
Bp (°C)
H vapor
—Liquid
Mp (°C)
H fusion
—Solid
Heat Lost (cal)
36.
Energy released to change 75.0 g water to ice at 0 °C:
75.0 g
38.
×
80.0 cal
1 g = 6.00 × 104 cal (60.0 kcal)
Energy released when water cools:
65.5 g
1.00 cal
× 1 g × °C × (55.5 – 0.0)°C = 3640 cal (3.64 kcal)
Energy released when water solidifies:
65.5 g
×
80.0 cal
= 5240 cal (5.24 kcal)
1 g Total heat energy released:
3640 cal + 5240 cal = 8880 cal (8.88 kcal)
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40.
Energy released when steam condenses:
155 g
×
540 cal
1 g = 83,700 cal (83.7 kcal)
Energy released when water cools:
155 g
1.00 cal
× 1 g × °C × (100.0 – 0.0)°C = 15,500 cal (15.5 kcal)
Energy released when water solidifies:
155 g
×
80.0 cal
= 12,400 cal (12.4 kcal)
1 g Total heat energy released:
83,700 cal + 15,500 cal + 12,400 cal = 111,600 cal (111.6 kcal)
42.
Energy released when steam cools:
90.5 g
0.48 cal
× 1 g × °C × (110.0 – 100.0)°C = 434 cal (0.434 kcal)
Energy released when steam condenses:
90.5 g
×
540 cal
1 g = 48,900 cal (48.9 kcal)
Energy released when water cools:
90.5 g
1.00 cal
× 1 g × °C × (100.0 – 0.0)°C = 9050 cal (9.05 kcal)
Energy released when water solidifies:
90.5 g
×
80.0 cal
= 7240 cal (7.24 kcal)
1 g Total heat energy released:
434 cal + 48,900 cal + 9050 cal + 7240 cal = 65,600 cal (65.6 kcal)
82
Chapter 11
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44.
0.500 kg = 5.00 × 102 g
Energy released when steam cools:
0.48 cal
5.00 × 102 g × 1 g × °C × (150.0 – 100.0)°C = 12,000 cal (12 kcal)
Energy released when steam condenses:
5.00 × 102 g
×
540 cal
5
2
1 g = 2.70 × 10 cal (2.70 × 10 kcal)
Energy released when water cools:
5.00 × 102 g
1.00 cal
× 1 g × °C × (100.0 – 0.0)°C = 5.00 × 104 cal (50.0 kcal)
Energy released when water solidifies:
5.00 × 102 g
×
80.0 cal
= 4.00 × 104 cal (40.0 kcal)
1 g Energy released when ice cools:
5.00 × 102 g
0.50 cal
× 1 g × °C × [0.0 – (– 50.0)]°C = 1.3 × 104 cal (13 kcal)
Total heat energy released:
12 kcal + 2.70 × 102 kcal + 50.0 kcal + 40.0 kcal + 13 kcal
= 385 kcal (385,000 cal)
Section 11.7 Structure of Water
46.
Water has an unusually high surface tension.
48.
The intermolecular bond existing between water molecules is a hydrogen bond.
50.
Net Dipole for a Water Molecule Shown with Standard Notation
O
H
H
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Section 11.8 Physical Properties of Water
52.
Liquid ammonia has the highest heat of fusion; water has the highest heat of
vaporization.
54.
Since a solid cube of ammonia floats in liquid ammonia, the liquid is more dense
than the solid.
56.
58.
60.
(a)
(b)
Liquid
H2 O or H2 Se
H2 S or H2 Te
Higher Boiling Point
H2 O (hydrogen bond attraction)
H2 Te (larger size, more attraction)
(a)
(b)
Liquid
H2 O or H2 Se
H2 S or H2 Te
Higher Heat of Vaporization
H2 O (hydrogen bond attraction)
H2 Te (larger size, more attraction)
Predicted Values for Radioactive H2 Po
We can estimate the physical properties for H2 Po by comparison to H2 Te. That
is, we can estimate an increase in the values from H2 Te to H2 Po by comparison
to the increase in the values from H2 Se to H2 Te. Thus,
Mp:
Bp:
Hfusion:
Hvapor:
–48.9 + [–48.9 – (–60.4)] = ~ –37.4 °C
–2.2 + [–2.2 – (–41.5)] = ~ 37.1 °C
1670 + (1670 – 899) = ~ 2441 cal/mol
5570 + (5570 – 4620) = ~ 6520 cal/mol
Section 11.9 Chemical Properties of Water
electrolysis
→
62.
2 H2 O(l)
64.
(a)
(b)
(c)
2 Rb(s) + 2 H2 O(l) → 2 RbOH(aq) + H2 (g)
Cs2 O(s) + H2 O(l) → 2 CsOH(aq)
P2 O5 (s) + 3 H2 O(l) → 2 H3 PO4 (aq)
66.
(a)
(b)
(c)
Ba(s) + 2 H2 O(l) → Ba(OH)2 (aq) + H2 (g)
CaO(s) + H2 O(l) → Ca(OH)2 (aq)
N2 O3 (g) + H2 O(l) → 2 HNO2 (aq)
68.
84
2 H2 (g) + O2 (g)
(a)
2 C3 H7 OH(l) + 9 O2 (g)
(b)
Ca(NO3 )2 • 4H2 O(s)
(c)
H2 CO3 (aq) + 2 KOH(aq)
Chapter 11
spark
→
Δ
→
→
6 CO2 (g) + 8 H2 O(g)
Ca(NO3 )2 (s) + 4 H2 O(g)
K2 CO3 (aq) + 2 HOH(l)
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70.
(a)
C 4 H9 OH(l) + 6 O2 (g)
(b)
KAl(SO4 )2 • 12H2 O(s)
(c)
H3 PO4 (aq) + 3 NaOH(aq)
spark
→
Δ
→
→
4 CO2 (g) + 5 H2 O(g)
KAl(SO4 )2 (s) + 12 H2 O(g)
Na3 PO4 (aq) + 3 HOH(l)
Section 11.10 Hydrates
72.
74.
76.
(a)
(b)
(c)
(d)
Chemical Formula
Sr(NO3 )2 • 6H2 O
Co(C2 H3 O2 )2 • 4H2 O
CuSO4 • 5H2 O
Cr(NO3 )3 • 9H2 O
(a)
(b)
(c)
(d)
Systematic Name
sodium acetate trihydrate
calcium sulfate dihydrate
potassium chromate tetrahydrate
zinc sulfate heptahydrate
(a)
Percentage of water in MnSO4 • H2 O
Systematic Name
strontium nitrate hexahydrate
cobalt(II) acetate tetrahydrate
copper(II) sulfate pentahydrate
chromium(III) nitrate
nonahydrate
Chemical Formula
NaC2 H3 O2 • 3H2 O
CaSO4 • 2H2 O
K2 CrO4 • 4H2 O
ZnSO4 • 7H2 O
MM of MnSO4 = 54.94 g + 32.07 g + 4(16.00 g) = 151.01 g
18.02 g
Percentage of water: 151.01 g + 18.02 g × 100% = 10.66% H2 O
(b)
Percentage of water in Sr(NO3 )2 • 6H2 O
MM of Sr(NO3 )2 = 87.62 g + 2(14.01 g) + 6(16.00 g) = 211.64 g
6(18.02 g)
Percentage of water: 211.64 g + 6(18.02 g) × 100% = 33.81% H2 O
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85
(c)
Percentage of water in Co(C2 H3 O2 )2 • 4H2 O
MM of Co(C2 H3 O2 )2 = 58.93 g + 4(12.01 g) + 6(1.01 g) + 4(16.00 g) = 177.03 g
4(18.02 g)
Percentage of water: 177.03 g + 4(18.02 g) × 100% = 28.94% H2 O
(d) Percentage of water in Cr(NO3 )3 • 9H2 O
MM of Cr(NO3 )3 = 52.00 g + 3(14.01 g) + 9(16.00 g) = 238.03 g
9(18.02 g)
Percentage of water: 238.03 g + 9(18.02 g)
78.
(a)
SrCl2 • XH2 O(s)
Δ
→
× 100% = 40.52% H2 O
SrCl2 (s) + X H2 O(g)
1 mol H2 O
18.5 g H2 O × 18.02 g H O = 1.03 mol H2 O
2
1 mol SrCl2
81.5 g SrCl2 × 158.52 g SrCl = 0.514 mol SrCl2
2
1.03
SrCl2 • 0.514 H2 O
1.03
0.514 = 2.00 ≈ 2
Chemical Formula: SrCl2 • 2H2 O
(b)
Δ
→
Ni(NO3 )2 • XH2 O(s)
Ni(NO3 )2 (s) + X H2 O(g)
1 mol H2 O
37.2 g H2 O × 18.02 g H O = 2.06 mol H2 O
2
1 mol Ni(NO3 )2
62.8 g Ni(NO3 )2 × 182.71 g Ni(NO ) = 0.344 mol Ni(NO3 )2
3 2
2.06
Ni(NO3 )2 • 0.344 H2 O
2.06
0.344 = 5.99 ≈ 6
Chemical Formula: Ni(NO3 )2 • 6H2 O
86
Chapter 11
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(c)
CoSO4 • XH2 O(s)
Δ
→
CoSO4 (s) + X H2 O(g)
1 mol H2 O
10.4 g H2 O × 18.02 g H O = 0.577 mol H2 O
2
1 mol CoSO4
89.6 g CoSO4 × 155.00 g CoSO = 0.578 mol CoSO4
4
0.578
CoSO4 • 0.577 H2 O
0.578
0.577
= 1.00 ≈ 1
Chemical Formula: CoSO4 • H2 O
Δ
→
(d) Na2 B4 O7 • XH2 O(s)
Na2 B4 O7 (s) + X H2 O(g)
1 mol H2 O
30.9 g H2 O × 18.02 g H O = 1.71 mol H2 O
2
1 mol Na2 B4 O7
69.1 g Na2 B4 O7 × 201.22 g Na B O = 0.343 mol Na2 B4 O7
2 4 7
1.71
Na2 B4 O7 • 0.343 H2 O
1.71
0.343 = 4.99 ≈ 5
Chemical Formula: Na2 B4 O7 • 5H2 O
General Exercises
80.
82.
Water comprises about two-thirds (~67%) of the human body.
(a)
(b)
(c)
(d)
Liquid
C 8 H1 8
C 2 H5 –Cl
HCOOH
C 2 H5 –O–C2 H5
Intermolecular Attraction
dispersion force
dipole force
hydrogen bond
dipole force
84.
The vapor pressure of ethanol is 0.500 atm (380 mm Hg) at ~65 °C. Therefore,
the boiling point of ethanol is ~65 °C at 0.500 atm.
86.
Ammonia, NH3 , has N–H bonds, so molecules can hydrogen bond and have a
strong intermolecular attraction. Thus, ammonia has high surface tension,
minimal surface area, and ammonia “raindrops” on Saturn will be spherical.
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87
Challenge Exercises
88.
Mass of ethylene glycol:
5.00 L
×
1000 mL
1 L
×
1.11 g
1 mL
= 5,550 g
Energy required to heat ethylene glycol:
5,550 g
0.561 cal
× 1 g × °C × (197.6 – 25.0)°C = 537,000 cal (537 kcal)
Energy required to vaporize ethylene glycol:
5,550 g
×
201 cal
1 g = 1,120,000 cal (1,120 kcal)
Total heat energy required:
537,000 cal + 1,120,000 cal = 1,660,000 cal (1,660 kcal)
Online Exercises
90.
88
The atmosphere of Saturn contains about 96% hydrogen and 3% helium. Trace
amounts of methane, ethane, propane, acetylene, and ammonia have also been
identified in the atmosphere of Saturn.
Chapter 11
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