Intermolecular Forces
CH2000: Introduction to General Chemistry, Plymouth State University
1. List each of the three intermolecular forces from weakest to strongest, along with the requirements
for a molecule to have it:
Weakest Force: _________________
Requirement(s): ____________________________
Force: _________________
Requirement(s): ____________________________
Strongest Force: _________________
Requirement(s): ____________________________
____________________________
2. Each of the following compounds would have only induced dipole forces. Circle the one with the
larger boiling point and explain your reasoning (note: these may be incomplete Lewis dot structures;
draw all the lone pairs of electrons that are missing ).
© Copyright Plymouth State University and Jeremiah Duncan. May be distributed freely for education purposes only.
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3. In addition to induced dipole forces, each of the following compounds would also have dipole-dipole
forces. Calculate the bond dipoles, indicate the overall dipole, circle the one with the larger boiling
point and explain your reasoning (note: these may be incomplete Lewis dot structures; draw all the lone
pairs of electrons that are missing ).
© Copyright Plymouth State University and Jeremiah Duncan. May be distributed freely for education purposes only.
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4. In addition to induced dipole and possibly dipole-dipole forces, each of the following compounds
would also have hydrogen bonding. For each molecule, draw an identical one next to it and indicate
where the hydrogen bond would form. Circle the one with the larger boiling point and explain your
reasoning (note: these may be incomplete Lewis dot structures; draw all the lone pairs of electrons that
are missing).
5. For which molecule in the each of the following pairs would you expect the stronger intermolecular
forces? Briefly explain by identifying the type(s) of intermolecular forces and relative strengths thereof
in samples of the molecules
a) CH3CH2CH2NH2 or H2NCH2CH2NH2
Explanation:
b) CH3CH3
or
Explanation:
H2CO
c) HF
or
HBr
Explanation:
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6. Rationalize the ordering of the melting points of the following compounds:
Acetone (CH3COCH3) m.p. = -95 °C
Acetic Acid (CH3CO2H) m.p. = 17 °C
Benzoic Acid (C6H5CO2H) m.p. = 122 °C
7. Rationalinze the difference in boiling points for the following pairs of compounds:
a) CH3OCH3 -25°C
CH3CH2OH 79°C
b) HF 20°C
HCl
c) CH3CH2CH2CH2CH3
d) CH3CH2CH3
-42°C
-85°C
36.2°C
CH3CH2CH3 -42°C
CH3OCH3 -25°C
8. Predict which substance in each of the following pairs would have the stronger intermolecular
forces. Identify the type(s) of forces present in your choice. Hint: Lewis dot structures may be helpful
a) CO2
or
OCS
b) PF3
or
PF5
c) SO3
or
SO2
© Copyright Plymouth State University and Jeremiah Duncan. May be distributed freely for education purposes only.
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