Review Intramolecular and Intermolecular Forces
For each multiple choice question that have WHY? at the end, please explain
the reasoning behind your answer chance. Some questions may have more
than one correct answer.
1. Which one of the following increases as the strength of the attractive
intermolecular forces increases?
a) The heat of vaporization
b) The normal boiling temperature
c) The extent of the deviations from the ideal gas law
d) The sublimation temperature of a solid
e) The vapor pressure of a liquid
WHY?
2. You are given the following boiling point data:
a) water, H2O
b) methanol, CH3OH
c) ethanol, CH3CH2OH
d) diethyl ether, CH3CH2OCH2CH3
e) ethylene glycol,HOCH2CH2OH
100oC
64.96oC
78.5oC
34.5oC
198oC
Which compound would you expect to have the lowest vapor pressure at room
temperature? WHY?
3. The boiling points of the Noble Gases increase going from helium to xenon.
What type of intermolecular forces is responsible for this trend?
a) dipole-dipole
b) hydrogen bonding
c) ion-ion attraction
d) London dispersion forces
e) network covalent forces
WHY?
4. Which one of the following boils at the highest temperature?
a) CF4
b) HF
c) Cu
d) KI
e) SiF4
WHY?
5. Which of the following is a correct listing in terms of decreasing boiling point?
a)
CCl4 > CH4 > H2O > H2S
b) CH4 > CCl4 > H2S > H2O
c)
H2O > H2S > CH4 > CCl4
d)
H2S > H2O > CCl4 > CH4
e)
H2O > H2S > CCl4 > CH4
WHY?
6. Describe London Dispersion forces, dipole-dipole attraction, and hydrogen
bonding. Include in your discussion the characteristics, which affect the magnitude
of each force (ie why does LDF change) and how each characteristic affects the
magnitude.
7. In which of the following processes are covalent bonds broken?
a) melting benzene
b) combustion of CH4
c) melting H2O
d) boiling C2H5OH
WHY?
8. In which process are the strongest bonds/forces being broken/overcome?
a) melting ice
b) melting iodine
c) boiling CCl4
d) melting NaCl
WHY?
9. Demonstrate the difference between intramolecular and intermolecular using
water. (10 pt)
Review for Heating Curve
Heating Curve.
1. Consider the following information for substance Q:
Hvap
Hfus
40 kJ/mol
10 kJ/mol
bp
mp
60°C
0°C
C(s)
C(l)
C(g)
2.0 J/g°C
8.0 J/g°C
4.0 J/g°C
A. Sketch the proportional heating curve for this substance starting at -10°C?
Briefly explain the significance of the plateaus and slopes. (10pt)
B. How much energy (in Joules) does it take to convert all of 0.333 kg of solid
substance Q at -5°C to a vapor that is at 80°C? Substance Q has a molar
mass of 45.0g/mol. (Read the questions carefully) (20pt)
Review for Solids and their Properties
1. How do ionic solids, molecular solids and atomic solids differ in their
construction? (What do you find at their lattice points?) Please draw an
example of each.
2. Classify as metallic, molecular, ionic or network covalent a solid that
a.
b.
c.
d.
e.
f.
is a nonconductor but conducts when melted
dissolves in water to give a non-conducting solution
melts below 100°C and reacts violently with water
conducts electricity as a solid
melts below 100°C to a give a non-conducting liquid
dissolves in water to a give a conducting solution
3. Of the four general types of solids which one(s)
a.
b.
c.
d.
e.
f.
are generally insoluble in water
are very high melting
conduct electricity as solids
are generally low boiling
are ductile and malleable
are generally nonvolatile
4. Classify the following species as being ionic, molecular, network covalent or
metallic at 25°C and 1 atm:
a.
b.
c.
d.
e.
PCl3
SiC
Bromine
MgO
Chromium
f. tungsten
g. IBr
h. quartz
i. iron (III) nitrate
j. carbon dioxide