#1
Which of the following is an example of a chemical change?
Burning wood
ExplanationTransformation of substances with new chemical identities.
#2
What is the SI unit of mass?
Kilogram
ExplanationBasic unit of mass in the International System of Units.
#3
What is the chemical symbol for gold?
Au
ExplanationAbbreviation used to represent an element.
#4
What is the chemical formula for water?
H2O
ExplanationRepresentation of the composition of a substance.
#5
What is the process of a liquid turning into a gas at its boiling point called?
Vaporization
ExplanationPhase transition from liquid to gas.
#6
Which of the following is NOT a characteristic of a solid?
Particles free to move
ExplanationSolids have fixed shape and volume due to tightly packed particles.
#7
What is the density of water at 4°C?
1 g/mL
ExplanationMass of water per unit volume at a specific temperature.
#8
Which of the following is NOT a physical property of matter?
Reactivity
ExplanationAbility to undergo chemical changes.
#9
What is the process of a gas turning into a liquid called?
Condensation
ExplanationPhase transition from gas to liquid.
#10
Which of the following is NOT a state of matter?
Molecule
ExplanationMolecule refers to a particle, not a state of matter.
#11
What is the law of conservation of mass?
Matter can neither be created nor destroyed
ExplanationTotal mass of a closed system remains constant over time.
#12
What happens to the density of a substance as its temperature increases?
Density decreases
ExplanationAs temperature rises, particles move faster, decreasing density.
#13
Which of the following statements describes a physical change?
Cooking an egg
ExplanationChange in form or appearance without altering chemical composition.
#14
What happens to the volume of a gas when pressure increases, assuming constant temperature?
Volume decreases
ExplanationInversely proportional relationship between pressure and volume at constant temperature.
#15
What is the process of a solid turning directly into a gas called?
Sublimation
ExplanationPhase transition from solid to gas without passing through the liquid phase.
#16
What happens to the pressure of a gas when its volume decreases, assuming constant temperature?
Pressure increases
ExplanationDirectly proportional relationship between pressure and volume at constant temperature.