CHEM 120 EXAM 1 PRACTICE QUESTIONS AND
DETAILED SOLUTIONS
◉ What happens to the kinetic-energy distribution of water
molecules when a solute is dissolved in water?
Answer: The overall kinetic-energy distribution does not
significantly change.
◉ What types of motion can molecules in a liquid have?
Answer: Molecules can undergo translational, rotational, and
vibrational motion.
◉ What types of motion do particles in a solid have?
Answer: Particles primarily vibrate around fixed positions.
◉ What does temperature measure at the molecular level?
Answer: Temperature is related to the average kinetic energy of
particles.
◉ What is the difference between an intramolecular bond and an
intermolecular force?
,Answer: Intramolecular bonds hold atoms together within a
molecule; intermolecular forces are attractions between separate
molecules.
◉ Is a covalent bond an intermolecular force?
Answer: No. A covalent bond is an intramolecular bond.
◉ What intermolecular forces exist between helium atoms?
Answer: Helium atoms experience London dispersion forces.
◉ Do ideal gases have intermolecular attractive forces?
Answer: No. The ideal-gas model assumes no intermolecular
attractions.
◉ Why can a real gas condense but an ideal gas cannot?
Answer: Real gases have intermolecular attractions that can cause
condensation.
◉ What is vaporization?
Answer: Liquid → gas
◉ What is condensation?
Answer: Gas → liquid
, ◉ What is melting/fusion?
Answer: Solid → liquid
◉ What is freezing?
Answer: Liquid → solid
◉ What is sublimation?
Answer: Solid → gas
◉ What is deposition?
Answer: Gas → solid
◉ What is the opposite of deposition?
Answer: Sublimation
◉ What is the opposite of sublimation?
Answer: Deposition
◉ What is the opposite of vaporization?
Answer: Condensation
DETAILED SOLUTIONS
◉ What happens to the kinetic-energy distribution of water
molecules when a solute is dissolved in water?
Answer: The overall kinetic-energy distribution does not
significantly change.
◉ What types of motion can molecules in a liquid have?
Answer: Molecules can undergo translational, rotational, and
vibrational motion.
◉ What types of motion do particles in a solid have?
Answer: Particles primarily vibrate around fixed positions.
◉ What does temperature measure at the molecular level?
Answer: Temperature is related to the average kinetic energy of
particles.
◉ What is the difference between an intramolecular bond and an
intermolecular force?
,Answer: Intramolecular bonds hold atoms together within a
molecule; intermolecular forces are attractions between separate
molecules.
◉ Is a covalent bond an intermolecular force?
Answer: No. A covalent bond is an intramolecular bond.
◉ What intermolecular forces exist between helium atoms?
Answer: Helium atoms experience London dispersion forces.
◉ Do ideal gases have intermolecular attractive forces?
Answer: No. The ideal-gas model assumes no intermolecular
attractions.
◉ Why can a real gas condense but an ideal gas cannot?
Answer: Real gases have intermolecular attractions that can cause
condensation.
◉ What is vaporization?
Answer: Liquid → gas
◉ What is condensation?
Answer: Gas → liquid
, ◉ What is melting/fusion?
Answer: Solid → liquid
◉ What is freezing?
Answer: Liquid → solid
◉ What is sublimation?
Answer: Solid → gas
◉ What is deposition?
Answer: Gas → solid
◉ What is the opposite of deposition?
Answer: Sublimation
◉ What is the opposite of sublimation?
Answer: Deposition
◉ What is the opposite of vaporization?
Answer: Condensation
