Honors Unit 9 –
Liquids and Solids
Homework & Handouts
Name: _______________________________________________
Miss Adams
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HW #1 - Intermolecular Forces
For each of the following compounds, first draw the Lewis structure. Then, determine if the
molecule is polar or nonpolar. Determine which intermolecular forces would be present in the
molecule and then circle the dominant IMF.
1)
nitrogen
2)
carbon tetrachloride
3)
H2S
4)
sulfur monoxide
5)
N2H2
6)
boron trihydride
7)
CH3OH
8)
SiH2O (Si is the central atom)
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Homework #2: Intermolecular Forces
1. Use the polarity and the structure to determine all of the intermolecular forces (IMF)
(London dispersion, dipole-dipole and/or hydrogen bonding) present, and then list them.
a)
CH4 - Polar (Y/N) _______________________________________________
b)
CHCl3 - Polar (Y/N)________________________________________________
c)
H2O - Polar (Y/N)________________________________________________
d)
NH3 - Polar (Y/N)________________________________________________
e)
PF5 - Polar (Y/N)_________________________________________________
f)
PH3 - Polar (Y/N)__________________________________________________
g)
CO2 - Polar (Y/N)__________________________________________________
2. The following compounds all have the same dominant IMF present:
Cl2
CF4
I2
H2
CCl4
a) What type of IMF is present in all of the above compounds?____________________
b) Rank the compounds in terms of increasing boiling point, and then briefly explain your
ranking.
3. All of the following compounds do NOT have the same type of dominant IMF’s. Rank
them in terms of increasing boiling point.
CH3OH
CO
CH4
O2
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Homework #3: Phase Changes & Heating Curves
1. Name the following phase changes:
Solid to liquid:___________________
Liquid to gas:______________________
Liquid to solid:___________________
Gas to liquid:______________________
Solid to gas:______________________
Gas to solid:_______________________
2.
Which line segment represents freezing of the substance?_______________________
3.
Which line segment represents vaporization of the substance? _________________
4.
Which line segment represents heating of the solid? ________________
5.
Which line segment represents heating of the liquid?________________
6.
Which line segment represents heating of the vapor?________________
7.
Which line segments represent increasing kinetic energy?________________
8.
Which line segments represent increasing potential energy?________________
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Homework #4: Phase Change Calculations
1. The enthalpy of vaporization (ΔHvap) of benzene, C6H6, is 30.8 kJ/mol. How much energy is
required to vaporize 1.28 mol of benzene?
2. The heat of fusion (ΔHfus) of benzene, C6H6, is 9.84 kJ/mol. How much energy is required to
melt 100.0 g of benzene?
3. The heat of fusion (ΔHfus) of water is 6.01 kJ/mol. What is the ΔH when 200.0 g of water are
frozen?
4. How much energy is required to heat 250.0 g of liquid water from 0 to 100 degrees C? The
specific heat of water is 4.18 J/goC.
5. How much energy is required to melt 250.0g of ice at 0 degrees C, and then to heat this same
quantity of melted ice to 100 degrees C? The heat of fusion of ice is 6.01 kJ/mole, and the
specific heat of water is 4.18 J/ goC
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Directions: Solve the following phase change problems by using the following constants, and the
equations in your reference booklet or class notes.
ΔHfus of water = 6.01 kJ/mol
ΔHvap of water = 40.7 kJ/mol.
c of water = 4.18 J/goC
c of steam = 1.84 J/goC
c of ice = 2.09 J/g oC.
1. How much energy is required to melt 50.0 g of ice at 0°C, and then to heat this same quantity
of melted ice to 100°C?
2. How much energy is required to heat 150.0 g of water from 25 to 100°C, and then to boil this
water (transform it all to steam?)
CONTINUE TO THE NEXT PAGE
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3. How much energy is required to heat 200. g of water from 25 to 125°C?
4. How much energy (report your answer with both a number and sign) is involved when 120. g
of water are cooled from 25.0°C to -25.0°C?
5. How much energy is required to heat 75 g of water from -85°C to 185°C?
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Homework #6: Vapor Pressure Curves
Answer the questions based on the following vapor pressure graph below:
a) The temperature at which water has a vapor pressure of 200 Torr is____________.
b) The vapor pressure of ethanol at 60°C is _________________________.
c) Which substance on the graph is most volatile at 20°C?______________________
d) What is the normal boiling point of each substance:
 Water__________________
 Ethanol_________________
 Diethyl ether____________
e) Which substance has the highest vapor pressure at 60°C, water or ethanol?______________
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Homework #7: Forces in Solids
1. Name the structure of each solid (network covalent, metallic or ionic) listed below and then briefly
state the reason for your choice.
a)
diamond:____________________
Why?_________________________________
b)
NaF:_________________________
Why?_________________________________
c)
Mg:__________________________
Why?__________________________________
d)
Cu:___________________________
Why?_________________________________
e)
MgO:_________________________
Why?________________________________
f)
graphite:________________________
Why?_________________________________
g)
Cr:______________________________
Why?_________________________________
h)
CuCl2 :___________________________
Why?_________________________________
2.
Name three physical properties for each type of solid below.
a. Network covalent:
a._______________________________________________
b._______________________________________________
c._______________________________________________
b. Metallic;
a._______________________________________________
b._______________________________________________
c._______________________________________________
c. Ionic;
a._______________________________________________
b._______________________________________________
c._______________________________________________
6.
a. Rank the following in terms of increased melting point.
NaCl
H2O
CCl4
CHCl3
b. Justify the reason for your ranking.
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