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CHEMISTRY: STRUCTURE AND PROPERTIES (3RD EDITION) — NIVALDO J.
TRO EXAM QUESTIONS AND CORRECT ANSWERS LATEST EDITION 2026
Chemistry: Structure and Properties (3rd Edition) — Nivaldo J. Tro
Original Practice Questions — Chemistry: Structure and Properties (3rd Edition)
Essentials: Units, Measurement, and Problem Solving (Questions 1–10)
1. Which of the following is a homogeneous mixture?
A) Mud and water
B) Sugar and coffee
C) Oil and water
D) Sand and iron filings
Answer: B — Sugar and coffee
Rationale: A homogeneous mixture has uniform composition throughout. Sugar dissolved in
coffee is homogeneous. Mud and water is heterogeneous .
2. How are gases different from solids and liquids?
A) Gases are compressible
B) Gases are always colorless
C) Gases have stronger intermolecular forces
D) Gases can only be made of atoms
Answer: A — Gases are compressible
Rationale: Gases have large spaces between particles, making them compressible. Solids and
liquids are not easily compressed .
3. A scientific law is best described as:
A) A brief statement that summarizes past observations and predicts future ones
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B) An explanation of why something happens
C) A mathematical formula that cannot be modified
D) A hypothesis that has been proven
Answer: A — A brief statement that summarizes past observations and predicts future ones
Rationale: A scientific law summarizes observations (e.g., law of conservation of mass). A theory
provides explanation .
4. Which of the following is an SI base unit?
A) Liter
B) Gram
C) Kelvin
D) Pound
Answer: C — Kelvin
Rationale: The kelvin (K) is the SI base unit for temperature. Liter is a derived unit, gram is not
the SI base unit for mass (kilogram is), and pound is not SI.
5. How many significant figures are in the measurement 0.00340 m?
A) 2
B) 3
C) 5
D) 6
Answer: B — 3
Rationale: Leading zeros are not significant. The digits 3, 4, and the trailing zero after the
decimal are significant: 3 significant figures.
6. Which of the following represents a chemical change?
A) Melting ice
B) Dissolving sugar in water
C) Rusting iron
D) Breaking glass
Answer: C — Rusting iron
Rationale: Rusting is a chemical change (new substance formed). Melting, dissolving, and
breaking are physical changes.
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7. The prefix "nano" represents:
A) 10⁻³
B) 10⁻⁶
C) 10⁻⁹
D) 10⁻¹²
Answer: C — 10⁻⁹
Rationale: Nano- (n) = 10⁻⁹. Micro- = 10⁻⁶, milli- = 10⁻³, pico- = 10⁻¹².
8. Which of the following is an example of an intensive property?
A) Mass
B) Volume
C) Density
D) Length
Answer: C — Density
Rationale: Intensive properties (e.g., density, temperature) do not depend on amount of
substance. Extensive properties (mass, volume) do.
9. Convert 25.0°C to Kelvin.
A) 298.15 K
B) 248.15 K
C) 273.15 K
D) 25.0 K
Answer: A — 298.15 K
Rationale: K = °C + 273.15 = 25.0 + 273.15 = 298.15 K.
10. Which of the following is a pure substance?
A) Air
B) Brass
C) Water
D) Sea water
Answer: C — Water
Rationale: Water (H₂O) is a compound (pure substance). Air, brass, and sea water are mixtures.
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Chapter 1: Atoms (Questions 11–25)
11. An element has three stable isotopes with masses of 27.977 amu, 28.976 amu, and 29.973
amu. The heavier two isotopes have abundances of 4.68% and 3.09%, respectively. What is
the atomic mass of the element?
A) 27.684 amu
B) 29.251 amu
C) 28.085 amu
D) 30.107 amu
Answer: C — 28.085 amu
Rationale: The element is silicon. Abundance of lightest isotope = 100% − 4.68% − 3.09% =
92.23%. Atomic mass = (0.9223)(27.977) + (0.0468)(28.976) + (0.0309)(29.973) = 28.085 amu .
12. Which of the following is NOT part of Dalton's atomic theory?
A) All matter is composed of atoms
B) Atoms of a given element are identical
C) Atoms can be subdivided into protons and neutrons
D) Atoms combine in simple whole-number ratios
Answer: C — Atoms can be subdivided into protons and neutrons
Rationale: Dalton's theory stated atoms are indivisible. Subatomic particles were discovered
later.
13. The number of protons in an atom is called the:
A) Mass number
B) Atomic number
C) Neutron number
D) Isotope number
Answer: B — Atomic number
Rationale: Atomic number (Z) = number of protons. Mass number = protons + neutrons.
14. An atom of ³⁵Cl has how many neutrons?
A) 17
B) 18
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CHEMISTRY: STRUCTURE AND PROPERTIES (3RD EDITION) — NIVALDO J.
TRO EXAM QUESTIONS AND CORRECT ANSWERS LATEST EDITION 2026
Chemistry: Structure and Properties (3rd Edition) — Nivaldo J. Tro
Original Practice Questions — Chemistry: Structure and Properties (3rd Edition)
Essentials: Units, Measurement, and Problem Solving (Questions 1–10)
1. Which of the following is a homogeneous mixture?
A) Mud and water
B) Sugar and coffee
C) Oil and water
D) Sand and iron filings
Answer: B — Sugar and coffee
Rationale: A homogeneous mixture has uniform composition throughout. Sugar dissolved in
coffee is homogeneous. Mud and water is heterogeneous .
2. How are gases different from solids and liquids?
A) Gases are compressible
B) Gases are always colorless
C) Gases have stronger intermolecular forces
D) Gases can only be made of atoms
Answer: A — Gases are compressible
Rationale: Gases have large spaces between particles, making them compressible. Solids and
liquids are not easily compressed .
3. A scientific law is best described as:
A) A brief statement that summarizes past observations and predicts future ones
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B) An explanation of why something happens
C) A mathematical formula that cannot be modified
D) A hypothesis that has been proven
Answer: A — A brief statement that summarizes past observations and predicts future ones
Rationale: A scientific law summarizes observations (e.g., law of conservation of mass). A theory
provides explanation .
4. Which of the following is an SI base unit?
A) Liter
B) Gram
C) Kelvin
D) Pound
Answer: C — Kelvin
Rationale: The kelvin (K) is the SI base unit for temperature. Liter is a derived unit, gram is not
the SI base unit for mass (kilogram is), and pound is not SI.
5. How many significant figures are in the measurement 0.00340 m?
A) 2
B) 3
C) 5
D) 6
Answer: B — 3
Rationale: Leading zeros are not significant. The digits 3, 4, and the trailing zero after the
decimal are significant: 3 significant figures.
6. Which of the following represents a chemical change?
A) Melting ice
B) Dissolving sugar in water
C) Rusting iron
D) Breaking glass
Answer: C — Rusting iron
Rationale: Rusting is a chemical change (new substance formed). Melting, dissolving, and
breaking are physical changes.
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7. The prefix "nano" represents:
A) 10⁻³
B) 10⁻⁶
C) 10⁻⁹
D) 10⁻¹²
Answer: C — 10⁻⁹
Rationale: Nano- (n) = 10⁻⁹. Micro- = 10⁻⁶, milli- = 10⁻³, pico- = 10⁻¹².
8. Which of the following is an example of an intensive property?
A) Mass
B) Volume
C) Density
D) Length
Answer: C — Density
Rationale: Intensive properties (e.g., density, temperature) do not depend on amount of
substance. Extensive properties (mass, volume) do.
9. Convert 25.0°C to Kelvin.
A) 298.15 K
B) 248.15 K
C) 273.15 K
D) 25.0 K
Answer: A — 298.15 K
Rationale: K = °C + 273.15 = 25.0 + 273.15 = 298.15 K.
10. Which of the following is a pure substance?
A) Air
B) Brass
C) Water
D) Sea water
Answer: C — Water
Rationale: Water (H₂O) is a compound (pure substance). Air, brass, and sea water are mixtures.
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Chapter 1: Atoms (Questions 11–25)
11. An element has three stable isotopes with masses of 27.977 amu, 28.976 amu, and 29.973
amu. The heavier two isotopes have abundances of 4.68% and 3.09%, respectively. What is
the atomic mass of the element?
A) 27.684 amu
B) 29.251 amu
C) 28.085 amu
D) 30.107 amu
Answer: C — 28.085 amu
Rationale: The element is silicon. Abundance of lightest isotope = 100% − 4.68% − 3.09% =
92.23%. Atomic mass = (0.9223)(27.977) + (0.0468)(28.976) + (0.0309)(29.973) = 28.085 amu .
12. Which of the following is NOT part of Dalton's atomic theory?
A) All matter is composed of atoms
B) Atoms of a given element are identical
C) Atoms can be subdivided into protons and neutrons
D) Atoms combine in simple whole-number ratios
Answer: C — Atoms can be subdivided into protons and neutrons
Rationale: Dalton's theory stated atoms are indivisible. Subatomic particles were discovered
later.
13. The number of protons in an atom is called the:
A) Mass number
B) Atomic number
C) Neutron number
D) Isotope number
Answer: B — Atomic number
Rationale: Atomic number (Z) = number of protons. Mass number = protons + neutrons.
14. An atom of ³⁵Cl has how many neutrons?
A) 17
B) 18
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