Question: Calcium fluoride forms a crystalline lattice in fluorite. Choose the best description of the packing of the calcium ions.
Answer Options:
A. Simple cubic
B. Face-centered cubic
C. Body-centered cubic
D. Hexagonal close-packed
E. Cubic close-packed
Answer: B. Face-centered cubic
Question: What happens to the conductivity of a semiconductor when the temperature increases?
Answer Options:
(fill-in-the-blank)
Answer: It increases
Question: Identify quartz (silicon dioxide) as one of the following types of solids.
Answer Options:
A. Molecular solid
B. Covalent network solid
C. Ionic solid
D. Metallic solid
E. Amorphous solid
Answer: B. Covalent network solid
Question: Identify potassium fluoride (KF) as one of the following types of solids.
Answer Options:
A. Molecular solid
B. Covalent network solid
C. Ionic solid
D. Metallic solid
E. Amorphous solid
Answer: C. Ionic solid
Question: What phase change is represented by the transition from A to C on a phase diagram (solid region A to liquid region C)?
Answer Options:
A. Sublimation
B. Melting (fusion)
C. Vaporization
D. Deposition
E. Condensation
Answer: B. Melting (fusion)
Question: What type of packing is shown in this unit cell?
Answer Options:
A. Simple cubic
B. Body-centered cubic (BCC)
C. Face-centered cubic (FCC)
D. Hexagonal close-packed (HCP)
E. Tetragonal
Answer: C. Face-centered cubic (FCC)
Question: Which one of the following would have the highest heat of vaporization?
Answer Options:
A. H₂O
B. CH₃OH
C. NH₃
D. CH₃CH₃
E. He
Answer: A. H₂O
Question: What is represented by B on a typical pressure-temperature phase diagram?
Answer Options:
A. Critical point
B. Triple point
C. Melting point at 1 atm
D. Boiling point at 1 atm
E. Sublimation point
Answer: C. Melting point at 1 atm
Question: What type of intermolecular forces do ammonia and hydrogen fluoride have in common?
Answer Options:
(duplicate of the first)
Answer: hydrogen bonding
Question: A phase change graph is shown below. Choose the image that best represents which phase(s) are present at point C (the upper plateau).
Answer Options:
A. All solid
B. All liquid
C. All gas
D. Liquid + gas
E. Solid + gas
Answer: D. Liquid + gas
Question: What is the empirical ratio of the two metals in the Au–Cu alloy shown?
Answer Options:
(fill-in-the-blank)
Answer: 3:1 (Au₃Cu)
Question: How many triple points are present on the phase diagram for elemental carbon?
Answer Options:
(fill-in-the-blank)
Answer: 1
Question: A phase change graph is shown below. Identify what phase(s) are present at point B (the middle plateau).
Answer Options:
A. Solid only
B. Solid + liquid
C. Liquid only
D. Liquid + gas
E. Gas only
Answer: B. Solid + liquid
Question: Which of the following steps is not part of structure determination by X-ray diffraction?
Answer Options:
A. Grow a suitable crystal
B. Mount the crystal on a diffractometer
C. Collect diffraction intensities
D. Solve the phase problem
E. Measure the density of the crystal
Answer: E. Measure the density of the crystal
Question: Which of the following might be best described by the following properties—white solid melting at 772 °C, solid does not conduct electricity, solid dissolves in water to form a conducting solution?
Answer Options:
A. Molecular solid
B. Metallic solid
C. Covalent network solid
D. Ionic solid
E. Amorphous solid
Answer: D. Ionic solid
Question: Which term is a measure of the resistance to flow in a liquid?
Answer Options:
(fill-in-the-blank)
Answer: viscosity
Question: Which of the following should exhibit the highest viscosity at 298 K?
Answer Options:
A. CH₄
B. CO₂
C. C₆H₆
D. C₂H₆O
E. Glycerol
Answer: E. Glycerol
Question: If a pressurized container of liquid CO₂ at 250 K is allowed to expand until the pressure is 10 atm, the CO₂ will exist as
Answer Options:
A. Solid
B. Liquid
C. Solid + liquid
D. Superheated vapor
E. Supercritical fluid
Answer: D. Superheated vapor
Question: What phase transition occurs when liquid tin at 700 K is compressed to 100 atm?
Answer Options:
A. Freezing (liquid → solid)
B. Melting (solid → liquid)
C. Vaporization (liquid → gas)
D. Condensation (gas → liquid)
E. Sublimation (solid → gas)
Answer: A. Freezing (liquid → solid)
Question: Which of the factors contributes to a low viscosity of a liquid?
Answer Options:
A. Strong intermolecular forces
B. Large molecular size
C. High molecular weight
D. Weak intermolecular forces
E. Extensive hydrogen bonding
Answer: D. Weak intermolecular forces
Question: Calculate the total number of atoms contained within this unit cell.
Answer Options:
(fill-in-the-blank)
Answer: 4 atoms
Question: What intermolecular forces are present in pure samples of both CH₃CH₂CH₂F and CH₃CH₂CH₂OH?
Answer Options:
(fill-in-the-blank)
Answer: dipole–dipole interactions and London dispersion forces
Question: Which of the following pairs correctly ranks the viscosity of the compounds (from lowest to highest)?
Answer Options:
A. CO₂ < CH₄ < H₂O < Glycerol
B. CH₄ < CO₂ < Glycerol < H₂O
C. H₂O < CH₄ < CO₂ < Glycerol
D. Glycerol < H₂O < CO₂ < CH₄
E. CH₄ < H₂O < CO₂ < Glycerol
Answer: A. CO₂ < CH₄ < H₂O < Glycerol
Question: Identify the supercritical fluid region in the phase diagram for CO₂.
Answer Options:
(fill-in-the-blank)
Answer: above the critical temperature and pressure
Question: Which one of the following phase changes would be endothermic?
Answer Options:
A. Freezing
B. Condensation
C. Vaporization
D. Deposition
E. Sublimation
Answer: C. Vaporization