CHEM ON-RAMPS: UNIT 3 (STATES OF MATTER) PART 2 EXAM
QUESTIONS AND CORRECT ANSWERS |2026/2027 UPDATED
|GUARANTEED PASS.
Dispersion (London) forces result from..
1.The formation of a loose covalent linkage between a hydrogen atom connected to a very
electronegative atom in a neighboring molecule.
2.Distortion of the electron cloud of an atom or molecule by the presence of nearby atoms or
molecules
3.Attraction between molecules in a liquid and molecules or atoms in a solid surface with which
the liquid is in contact.
4.Attractive forces between a molecule at the surface of the liquid and those beneath it which
are not balanced by corresponding forces from above.
5.The balance of attractive and repulsive forces between two polar molecules. - Answer -
2.Distortion of the electron cloud of an atom or molecule by the presence of nearby atoms or
molecules
Which of the following statements about intermolecular forces is correct?
a)Polar compounds are not able to form instantaneous dipoles
b)Compounds exhibiting only dispersion forces are not able to form solids
c)Dispersion forces are formed by the creation of instantaneous dipoles in otherwise nonpolar
molecules
d)Permanent dipoles form only in molecules with symmetrical geometries - Answer -
c)Dispersion forces are formed by the creation of instantaneous dipoles in otherwise nonpolar
molecules
H bonding looking at the graph - Answer -•Note the normal linear relationship between size of
compound and IMF. As shell increases, # of e-increases, and IMF increases
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,•There are 3 exceptions: NH3, H2O, HF which abruptly increase IMF even though they have
small dispersion
•This is attributed to ΔEN NH (0.9), OF (1.4), HF (1.9) which prompts stronger O -H ... O -H
attractions•The unusual behavior of H2O is because of H-bonds
Is a type of polar dipole-dipole force
Substances with H-bonding forces also have dipole-dipole and dispersion forces
ONLY occurs when between molecules with H-F, H-O, and/or H-N bonds
Strongest intermolecular force - Answer -Hydrogen Bonding
How would a hydrogen bond of H2O look like? - Answer -The hydrogen part of one H2O
molecule would be connected/attracted to the Oxygen part of the other H2O molecule.
rank : NH3, H2O, and HF - Answer -NH3 < HF < H2O
NH3: 3 H-bonds but small ΔEN
HF: Largest ΔEN
H2O: Larger ΔEN and 2 H-bonds
True/False: H-F is the only HF bond. In contrast, OH shows up as multiple H-bonds in sugars
which is why they are so sticky - Answer -True
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, Which of the following is NOT a characteristic of a hydrogen bond?a)It can occur when
hydrogen is covalently bound to very electronegative elements like F, Br, Cl, and I
b)It is weaker than a covalent bond
c)It is stronger than other dipole-dipole interactions
d)It is responsible for the unusual physical properties of water - Answer -a)It can occur when
hydrogen is covalently bound to very electronegative elements like F, Br, Cl, and I
How to assign IMF of single compound. - Answer -If non-polar like CH4dispersion
If polar like CH3Cl permanent dipole
If H-F, O-F, N-H like CH3OH H-bonding
If salt like Na+Cl-ionic
Note* the Answer is the most dominant force of each molecule or ion
Identify the dominant intermolecular force in the following species, respectively: RbCl,
C6H6(benzene), HI, Fe2O3, CH2NH.
a) ionic forced
b) hydrogen bonding
c) dipole-dipole
d) instantaneous dipoles
1.a, c, c, d, b
2.c, d, a, a, b
3.a, b, c, b, a
4.a, b, d, a, c
5.a, d, c, a, b
6.c, b, d, c, c
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QUESTIONS AND CORRECT ANSWERS |2026/2027 UPDATED
|GUARANTEED PASS.
Dispersion (London) forces result from..
1.The formation of a loose covalent linkage between a hydrogen atom connected to a very
electronegative atom in a neighboring molecule.
2.Distortion of the electron cloud of an atom or molecule by the presence of nearby atoms or
molecules
3.Attraction between molecules in a liquid and molecules or atoms in a solid surface with which
the liquid is in contact.
4.Attractive forces between a molecule at the surface of the liquid and those beneath it which
are not balanced by corresponding forces from above.
5.The balance of attractive and repulsive forces between two polar molecules. - Answer -
2.Distortion of the electron cloud of an atom or molecule by the presence of nearby atoms or
molecules
Which of the following statements about intermolecular forces is correct?
a)Polar compounds are not able to form instantaneous dipoles
b)Compounds exhibiting only dispersion forces are not able to form solids
c)Dispersion forces are formed by the creation of instantaneous dipoles in otherwise nonpolar
molecules
d)Permanent dipoles form only in molecules with symmetrical geometries - Answer -
c)Dispersion forces are formed by the creation of instantaneous dipoles in otherwise nonpolar
molecules
H bonding looking at the graph - Answer -•Note the normal linear relationship between size of
compound and IMF. As shell increases, # of e-increases, and IMF increases
1|Page
,•There are 3 exceptions: NH3, H2O, HF which abruptly increase IMF even though they have
small dispersion
•This is attributed to ΔEN NH (0.9), OF (1.4), HF (1.9) which prompts stronger O -H ... O -H
attractions•The unusual behavior of H2O is because of H-bonds
Is a type of polar dipole-dipole force
Substances with H-bonding forces also have dipole-dipole and dispersion forces
ONLY occurs when between molecules with H-F, H-O, and/or H-N bonds
Strongest intermolecular force - Answer -Hydrogen Bonding
How would a hydrogen bond of H2O look like? - Answer -The hydrogen part of one H2O
molecule would be connected/attracted to the Oxygen part of the other H2O molecule.
rank : NH3, H2O, and HF - Answer -NH3 < HF < H2O
NH3: 3 H-bonds but small ΔEN
HF: Largest ΔEN
H2O: Larger ΔEN and 2 H-bonds
True/False: H-F is the only HF bond. In contrast, OH shows up as multiple H-bonds in sugars
which is why they are so sticky - Answer -True
2|Page
, Which of the following is NOT a characteristic of a hydrogen bond?a)It can occur when
hydrogen is covalently bound to very electronegative elements like F, Br, Cl, and I
b)It is weaker than a covalent bond
c)It is stronger than other dipole-dipole interactions
d)It is responsible for the unusual physical properties of water - Answer -a)It can occur when
hydrogen is covalently bound to very electronegative elements like F, Br, Cl, and I
How to assign IMF of single compound. - Answer -If non-polar like CH4dispersion
If polar like CH3Cl permanent dipole
If H-F, O-F, N-H like CH3OH H-bonding
If salt like Na+Cl-ionic
Note* the Answer is the most dominant force of each molecule or ion
Identify the dominant intermolecular force in the following species, respectively: RbCl,
C6H6(benzene), HI, Fe2O3, CH2NH.
a) ionic forced
b) hydrogen bonding
c) dipole-dipole
d) instantaneous dipoles
1.a, c, c, d, b
2.c, d, a, a, b
3.a, b, c, b, a
4.a, b, d, a, c
5.a, d, c, a, b
6.c, b, d, c, c
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