UNE General Chemistry II Midterm
Practice Exam – University of New
England (UNE) – 2026/2027 Academic
Year – Verified Questions and Answers
for Undergraduate Chemistry and Pre-
Health Students
SECTION 1: INTERMOLECULAR FORCES & PHASE CHANGES
Question 1
A hydrogen bond is characterized by:
A) The attraction of temporary dipoles produced by random electron motion
asymmetries
B) The electrostatic attraction between permanent dipoles in any polar molecule
C) A highly concentrated partial charge interaction between an H atom and F, O, or N
atoms
D) The covalent sharing of electrons between two atoms in a molecule
Answer: C
,Rationale: A hydrogen bond is a special type of dipole-dipole interaction that occurs
when a hydrogen atom is bonded to a highly electronegative atom (F, O, or N). The
partial positive charge on H is strongly attracted to the partial negative charge on F, O,
or N of another molecule. This is much stronger than typical dipole-dipole interactions.
Option A describes London dispersion forces, B describes general dipole-dipole forces,
and D describes covalent bonds .
Question 2
Which of the following will have the strongest dipole-dipole attractions?
A) NCl₃
B) CCl₄
C) BCl₃
D) Cl₂
Answer: A
Rationale: NCl₃ is asymmetrical and has a significant dipole moment due to the
electronegativity difference between N and Cl. CCl₄ and Cl₂ are nonpolar molecules with
symmetrical structures that cancel dipoles. BCl₃ is trigonal planar and nonpolar despite
polar bonds because the bond dipoles cancel. Dipole-dipole forces require a net
molecular dipole, which only NCl₃ possesses .
Question 3
A cohesive force is:
A) The result of intermolecular forces that attract identical molecules
B) The result of intermolecular forces that attract different molecules together
,C) The result of covalent interactions between atoms in a molecule
D) Always stronger than an adhesive force
Answer: A
Rationale: Cohesive forces are the intermolecular attractions between identical
molecules. For example, water-water hydrogen bonding represents cohesion. Adhesive
forces (Option B) are attractions between different molecules. Cohesive forces are not
necessarily stronger than adhesive forces (Option D), and covalent interactions (Option
C) are intramolecular, not intermolecular .
Question 4
Which intermolecular force is present in ALL molecules?
A) Hydrogen bonding
B) Dipole-dipole interactions
C) London dispersion forces
D) Ionic bonding
Answer: C
Rationale: London dispersion forces (LDFs) are present in all molecules due to
temporary fluctuations in electron distribution. They are the only intermolecular force in
nonpolar molecules and exist alongside other forces in polar molecules. Hydrogen
bonding requires specific atoms, dipole-dipole requires permanent dipoles, and ionic
bonding is not an intermolecular force .
, Question 5
Which substance would have the highest boiling point?
A) H₂O
B) H₂S
C) H₂Se
D) H₂Te
Answer: A
Rationale: H₂O has the highest boiling point due to hydrogen bonding, which is
significantly stronger than the dipole-dipole and London dispersion forces present in
the other hydrogen chalcogenides (H₂S, H₂Se, H₂Te). Although molecular weight
increases down the group, the exceptional strength of hydrogen bonding in water
dominates the trend .
Question 6
An adhesive force:
A) Is the result of intermolecular forces that attract different molecules together
B) Is the result of intermolecular forces that attract identical molecules
C) Is always stronger than a cohesive force
D) Results from covalent bond formation between molecules
Answer: A
Rationale: An adhesive force is the result of intermolecular forces that attract different
molecules together. For example, the attraction between water molecules and a glass
surface is adhesion. This contrasts with cohesive forces, which attract identical
molecules. Adhesive forces are not always stronger than cohesive forces .
Practice Exam – University of New
England (UNE) – 2026/2027 Academic
Year – Verified Questions and Answers
for Undergraduate Chemistry and Pre-
Health Students
SECTION 1: INTERMOLECULAR FORCES & PHASE CHANGES
Question 1
A hydrogen bond is characterized by:
A) The attraction of temporary dipoles produced by random electron motion
asymmetries
B) The electrostatic attraction between permanent dipoles in any polar molecule
C) A highly concentrated partial charge interaction between an H atom and F, O, or N
atoms
D) The covalent sharing of electrons between two atoms in a molecule
Answer: C
,Rationale: A hydrogen bond is a special type of dipole-dipole interaction that occurs
when a hydrogen atom is bonded to a highly electronegative atom (F, O, or N). The
partial positive charge on H is strongly attracted to the partial negative charge on F, O,
or N of another molecule. This is much stronger than typical dipole-dipole interactions.
Option A describes London dispersion forces, B describes general dipole-dipole forces,
and D describes covalent bonds .
Question 2
Which of the following will have the strongest dipole-dipole attractions?
A) NCl₃
B) CCl₄
C) BCl₃
D) Cl₂
Answer: A
Rationale: NCl₃ is asymmetrical and has a significant dipole moment due to the
electronegativity difference between N and Cl. CCl₄ and Cl₂ are nonpolar molecules with
symmetrical structures that cancel dipoles. BCl₃ is trigonal planar and nonpolar despite
polar bonds because the bond dipoles cancel. Dipole-dipole forces require a net
molecular dipole, which only NCl₃ possesses .
Question 3
A cohesive force is:
A) The result of intermolecular forces that attract identical molecules
B) The result of intermolecular forces that attract different molecules together
,C) The result of covalent interactions between atoms in a molecule
D) Always stronger than an adhesive force
Answer: A
Rationale: Cohesive forces are the intermolecular attractions between identical
molecules. For example, water-water hydrogen bonding represents cohesion. Adhesive
forces (Option B) are attractions between different molecules. Cohesive forces are not
necessarily stronger than adhesive forces (Option D), and covalent interactions (Option
C) are intramolecular, not intermolecular .
Question 4
Which intermolecular force is present in ALL molecules?
A) Hydrogen bonding
B) Dipole-dipole interactions
C) London dispersion forces
D) Ionic bonding
Answer: C
Rationale: London dispersion forces (LDFs) are present in all molecules due to
temporary fluctuations in electron distribution. They are the only intermolecular force in
nonpolar molecules and exist alongside other forces in polar molecules. Hydrogen
bonding requires specific atoms, dipole-dipole requires permanent dipoles, and ionic
bonding is not an intermolecular force .
, Question 5
Which substance would have the highest boiling point?
A) H₂O
B) H₂S
C) H₂Se
D) H₂Te
Answer: A
Rationale: H₂O has the highest boiling point due to hydrogen bonding, which is
significantly stronger than the dipole-dipole and London dispersion forces present in
the other hydrogen chalcogenides (H₂S, H₂Se, H₂Te). Although molecular weight
increases down the group, the exceptional strength of hydrogen bonding in water
dominates the trend .
Question 6
An adhesive force:
A) Is the result of intermolecular forces that attract different molecules together
B) Is the result of intermolecular forces that attract identical molecules
C) Is always stronger than a cohesive force
D) Results from covalent bond formation between molecules
Answer: A
Rationale: An adhesive force is the result of intermolecular forces that attract different
molecules together. For example, the attraction between water molecules and a glass
surface is adhesion. This contrasts with cohesive forces, which attract identical
molecules. Adhesive forces are not always stronger than cohesive forces .
