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During the phase change from liquid to gas, which of the following best explains why temperature remains constant even when heat is continuously applied?
A. The added heat is lost to the surroundings
B. The heat increases the kinetic energy of the particles
C. The heat is used to break intermolecular forces
D. The heat is stored as chemical potential energy
C. The heat is used to break intermolecular forces
A beaker contains ice at 0°C. Which statement is correct as more heat is added?
A. Both the temperature and kinetic energy increase
B. Only the temperature increases until all the ice melts
C. Temperature remains constant until all ice melts
D. The ice will evaporate without melting
C. Temperature remains constant until all ice melts
Why does water require more energy to vaporize than to melt?
A. Vaporization occurs at a higher temperature
B. Molecules are closer in the gas phase
C. Vaporization breaks all chemical bonds
D. Vaporization requires completely overcoming intermolecular forces
D. Vaporization requires completely overcoming intermolecular forces
In the phase diagram of water, what phase change occurs when moving directly from point A (solid) to point C (gas), bypassing the liquid phase?
A. Melting
B. Condensation
C. Deposition
D. Sublimation
D. Sublimation
You take an ice cube out of the freezer and leave it on a plate. After a while, it turns into a puddle of water. What phase change occurred?
A. Freezing
B. Condensation
C. Melting
D. Sublimation
C. Melting
Frost forms on your car window overnight, even though there is no rain. What phase change occurred?
A. Freezing
B. Deposition
C. Sublimation
D. Melting
B. Deposition
In very dry and cold conditions, snow disappears without melting. What phase change is happening?
A. Deposition
B. Sublimation
C. Freezing
D. Condensation
B. Sublimation
Which of the following is the correct term for the phase change from a plasma to gas?
A. Sublimation
B. Ionization
C. Recombination
D. Condensation
C. Recombination
Which state of matter has particles that vibrate in fixed positions and are arranged in a regular pattern?
A. Liquid
B. Gas
C. Plasma
D. Solid
D. Solid
Which property of liquids allows them to be poured and take the shape of their container?
A. Low density
B. Flowability
C. High rigidity
D. Low compressibility
B. Flowability
Which of the following best describes an intramolecular force?
A. Attraction between two different molecules
B. Force within a molecule holding atoms together
C. Force that exists only in gases
D. Temporary attraction between nonpolar molecules
B. Force within a molecule holding atoms together
Which of the following intermolecular forces is the weakest?
A. Hydrogen bonding
B. Ionic bonding
C. Dipole-dipole
D. London dispersion forces
D. London dispersion forces
Which following molecules are most likely to exhibit hydrogen bonding?
A. CH₄ and CO₂
B. H₂O and NH₃
C. NaCl and KBr
D. O₂ and H₂
B. H₂O and NH₃
Why do liquids have definite volume but no definite shape?
A. Their particles are stationary
B. They have equal attraction in all directions
C. They can compress into smaller spaces
D. Particles are close but can move around each
D. Particles are close but can move around each
Which feature of metallic bonds allows metals to conduct electricity well?
A. Regular crystal patterns
B. Positive ions bonded to negative ones
C. Delocalized, mobile electrons
D. Weak intermolecular forces
C. Delocalized, mobile electrons
Which explanation best describes why liquids are less compressible than gases?
A. Liquid particles are already close together
B. Liquids expand freely
C. Gases are denser
D. Liquids have no volume
A. Liquid particles are already close together
Ice floats on water. What does this tell us about the density of solid vs. liquid water?
A. Solid water is more dense than liquid
B. They have equal density
C. Solid water is less dense due to the arrangement of molecules
D. Ice is heavier but takes up less space
C. Solid water is less dense due to the arrangement of molecules
Water is called a “universal solvent” because:
A. It can dissolve any substance
B. It reacts with all metals
C. It is polar and can dissolve many polar substances
D. It breaks down into hydrogen and oxygen
C. It is polar and can dissolve many polar substances
How can you distinguish a molecular solid from an ionic solid?
A. Molecular solids conduct electricity in water
B. Molecular solids are usually brittle
C. Molecular solids are held by intermolecular forces
D. Molecular solids are metals
C. Molecular solids are held by intermolecular forces
Which property of water allows it to moderate Earth's climate by absorbing and releasing heat slowly?
A. Latent Heat
B. High specific heat
C. Heat of Vaporization
D. Heat of Fusion
B. High specific heat
What type of intermolecular force exists between two nonpolar molecules like nitrogen (N₂)?
A. Dipole-dipole
B. Hydrogen bonding
C. London dispersion forces
D. Ionic bonding
C. London dispersion forces
What is the primary intermolecular force in ammonia (NH₃)?
A. Hydrogen bonding
B. London dispersion
C. Dipole-dipole
D. Ionic bonding
A. Hydrogen bonding
Which of the following statements is TRUE about dipole-dipole forces?
A. They occur only in ionic compounds.
B. They are stronger than hydrogen bonds.
C. They occur between polar molecules.
D. They occur between nonpolar molecules.
C. They occur between polar molecules.
What causes a water molecule to be polar?
A. Equal sharing of electrons between atoms
B. Hydrogen being more electronegative than oxygen
C. Unequal sharing of electrons due to O2 being more electronegative than hydrogen
D. Equal distribution of charge across the molecule
C. Unequal sharing of electrons due to O2 being more electronegative than hydrogen
Which of the following is NOT a property of most metals?
A. High melting point
B. Sonorous
C. Insulator of electricity
D. Lustrous (shiny) appearance
B. Sonorous