UNE General Chemistry II Midterm Test Bank: Weeks 1–7 Complete Practice Questions with Verified Answers – Graded A+ Study Guide.

UNE General Chemistry II Midterm Test Bank:
Weeks 1–7 Complete Practice Questions
with Verified Answers – Graded A+ Study
Guide.




WEEK 1: Intermolecular Forces & Properties of Liquids
Question 1: Which of the following will have the highest vapor pressure?

 A) 0.1 M NaCl in water
 B) 0.5 M NaCl in water
 C) 1.0 M NaCl in water
 D) 2.0 M NaCl in water

Correct Answer: A) 0.1 M NaCl in water
Explanation: Vapor pressure is a colligative property that depends on the number of solute
particles in solution. The vapor pressure of a solution is lowered by the presence of solute
particles (Raoult's Law). A 0.1 M solution has the fewest solute particles, so it experiences
the smallest vapor pressure lowering and therefore has the highest vapor pressure .




Question 2: What type of intermolecular force is present between water molecules?

 A) London dispersion forces only
 B) Dipole-dipole forces only
 C) Hydrogen bonding
 D) Ionic bonding

Correct Answer: C) Hydrogen bonding
Explanation: Water molecules exhibit hydrogen bonding, which is a particularly strong

, type of dipole-dipole interaction that occurs when hydrogen is bonded to highly
electronegative atoms like oxygen, nitrogen, or fluorine. This explains water's unusually
high boiling point and surface tension .




Question 3: An adhesive force is best described as:

 A) The attraction between molecules of the same substance
 B) The attraction between molecules of different substances
 C) The repulsion between molecules of the same substance
 D) The force that holds atoms together in a molecule

Correct Answer: B) The attraction between molecules of different substances
Explanation: Adhesive forces are intermolecular forces that attract different types of
molecules to each other. This is the opposite of cohesive forces, which are attractions
between molecules of the same substance .




Question 4: Metallic solids are composed of:

 A) Atoms with nuclei in a "sea" of delocalized electrons
 B) Ions held together by electrostatic forces
 C) Covalently bonded atoms in a network structure
 D) Individual molecules held by London dispersion forces

Correct Answer: A) Atoms with nuclei in a "sea" of delocalized electrons
Explanation: Metallic solids have a unique structure where metal cations are surrounded
by a "sea" of delocalized electrons that can move freely throughout the solid. This electron
sea model explains the characteristic properties of metals, including electrical conductivity,
malleability, and ductility .




Question 5: Which intermolecular force is present in all molecules regardless of
polarity?

, A) Hydrogen bonding
 B) Dipole-dipole forces
 C) London dispersion forces
 D) Ion-dipole forces

Correct Answer: C) London dispersion forces
Explanation: London dispersion forces (also called induced dipole-induced dipole forces)
are the weakest type of intermolecular force but are present in all molecules. They arise
from temporary fluctuations in electron distribution that create instantaneous dipoles .




Question 6: Acetonitrile (CH₃CN) evaporates very quickly at room temperature and feels
cold when evaporating. If ΔHvap for acetonitrile is 34.2 kJ/mol, how much heat is
removed when 1.0 mole of acetonitrile evaporates?

 A) 34.2 J
 B) 34.2 kJ
 C) 342 kJ
 D) 3.42 kJ

Correct Answer: B) 34.2 kJ
Explanation: The enthalpy of vaporization (ΔHvap) is the amount of heat required to
vaporize one mole of a liquid at constant temperature. For acetonitrile, ΔHvap = 34.2
kJ/mol, so vaporizing 1.0 mole requires (and removes from the surroundings) 34.2 kJ of
heat. This is why the liquid feels cold upon evaporation—heat is absorbed from the skin .




Question 7: Which of the following correctly ranks the strength of intermolecular forces
from strongest to weakest?

 A) Hydrogen bonding > dipole-dipole > London dispersion
 B) Dipole-dipole > hydrogen bonding > London dispersion
 C) London dispersion > dipole-dipole > hydrogen bonding
 D) Hydrogen bonding > London dispersion > dipole-dipole

Correct Answer: A) Hydrogen bonding > dipole-dipole > London dispersion
Explanation: Hydrogen bonding is the strongest type of intermolecular force, followed by

, dipole-dipole interactions, with London dispersion forces being the weakest. The strength
of intermolecular forces determines physical properties such as boiling points, melting
points, and vapor pressure .




Question 8: Which substance would you expect to have the highest boiling point?

 A) CH₄ (methane)
 B) H₂O (water)
 C) H₂S (hydrogen sulfide)
 D) HCl (hydrogen chloride)

Correct Answer: B) H₂O (water)
Explanation: Water has the highest boiling point among these options due to hydrogen
bonding, which is much stronger than the dipole-dipole forces in H₂S and HCl, or the
London dispersion forces in CH₄. The strong hydrogen bonds require more energy to break
during vaporization .




Question 9: The surface tension of a liquid is due to:

 A) The cohesive forces between molecules at the surface
 B) The adhesive forces between molecules at the surface
 C) The repulsive forces between molecules at the surface
 D) The gravitational forces acting on the surface molecules

Correct Answer: A) The cohesive forces between molecules at the surface
Explanation: Surface tension arises because molecules at the surface of a liquid experience
net inward attractive forces (cohesive forces) since they have fewer neighbors to interact
with compared to molecules in the bulk. This creates a "skin" effect at the surface and
minimizes surface area .




Question 10: Which of the following would have the highest viscosity?