,Chem 103 Module 1 | Actual Exam study Questions and Answers + Rationales
| 2026/27 Updates | 100% correct
1. Which branch of chemistry focuses on the composition, properties, and reactions of carbon-
containing compounds?
A) Analytical Chemistry
B) Physical Chemistry
C) Organic Chemistry
D) Nuclear Chemistry
Correct Answer: Organic Chemistry
Rationale: Organic chemistry is the branch that specifically studies compounds containing
carbon, particularly those with carbon-hydrogen bonds . This distinguishes it from analytical,
physical, and nuclear chemistry, which focus on other aspects of matter.
2. What is the difference between a hypothesis and a theory?
A) A hypothesis is a broad explanation, while a theory is an educated guess
B) A hypothesis is an initial testable explanation, while a theory is a well-substantiated
explanation supported by extensive evidence
C) A hypothesis has been proven, while a theory has not
D) There is no functional difference between the two
Correct Answer: A hypothesis is an initial testable explanation, while a theory is a well-
substantiated explanation supported by extensive evidence
, Rationale: A hypothesis is a proposed explanation that can be tested through
experimentation, whereas a theory is a broad, well-supported explanation that has withstood
rigorous testing and is widely accepted in the scientific community .
3. Which statement correctly describes particles in a solid state at the submicroscopic level?
A) Particles move freely and rapidly, colliding with each other
B) Particles are tightly packed in a regular arrangement and vibrate in fixed positions
C) Particles are close but can slide past one another
D) Particles have no attractive forces between them
Correct Answer: Particles are tightly packed in a regular arrangement and vibrate in fixed
positions
Rationale: In solids, particles are held in fixed positions within a regular, repeating pattern
(lattice) and only vibrate slightly around these positions . This accounts for the definite shape
and volume characteristic of solids.
4. Which of the following is an example of a physical property?
A) Flammability
B) Density
C) Reactivity with oxygen
D) Corrosiveness
Correct Answer: Density
Rationale: Density is a physical property because it can be measured without changing a
substance's chemical identity . Flammability, reactivity, and corrosiveness are chemical
properties because they describe how a substance undergoes a chemical change .
, 5. Which of the following describes a chemical change?
A) Ice melting into water
B) Water boiling
C) Iron rusting in moist air
D) Crushing aluminum foil
Correct Answer: Iron rusting in moist air
Rationale: Rusting is a chemical change because it forms a new substance, iron oxide .
Melting, boiling, and crushing are physical changes as they do not alter the chemical
composition of the matter.
6. A mixture of sand and iron filings is separated using a magnet. This separation technique is
possible because:
A) It is a homogeneous mixture
B) It is a compound
C) The iron filings are a pure substance with a unique physical property (magnetism)
D) It is a solution
Correct Answer: The iron filings are a pure substance with a unique physical property
(magnetism)
Rationale: The iron filings retain their physical property of being magnetic. This allows for a
physical separation from the sand, which is not magnetic, based on a difference in physical
properties.
7. Which SI unit is used to measure mass?
| 2026/27 Updates | 100% correct
1. Which branch of chemistry focuses on the composition, properties, and reactions of carbon-
containing compounds?
A) Analytical Chemistry
B) Physical Chemistry
C) Organic Chemistry
D) Nuclear Chemistry
Correct Answer: Organic Chemistry
Rationale: Organic chemistry is the branch that specifically studies compounds containing
carbon, particularly those with carbon-hydrogen bonds . This distinguishes it from analytical,
physical, and nuclear chemistry, which focus on other aspects of matter.
2. What is the difference between a hypothesis and a theory?
A) A hypothesis is a broad explanation, while a theory is an educated guess
B) A hypothesis is an initial testable explanation, while a theory is a well-substantiated
explanation supported by extensive evidence
C) A hypothesis has been proven, while a theory has not
D) There is no functional difference between the two
Correct Answer: A hypothesis is an initial testable explanation, while a theory is a well-
substantiated explanation supported by extensive evidence
, Rationale: A hypothesis is a proposed explanation that can be tested through
experimentation, whereas a theory is a broad, well-supported explanation that has withstood
rigorous testing and is widely accepted in the scientific community .
3. Which statement correctly describes particles in a solid state at the submicroscopic level?
A) Particles move freely and rapidly, colliding with each other
B) Particles are tightly packed in a regular arrangement and vibrate in fixed positions
C) Particles are close but can slide past one another
D) Particles have no attractive forces between them
Correct Answer: Particles are tightly packed in a regular arrangement and vibrate in fixed
positions
Rationale: In solids, particles are held in fixed positions within a regular, repeating pattern
(lattice) and only vibrate slightly around these positions . This accounts for the definite shape
and volume characteristic of solids.
4. Which of the following is an example of a physical property?
A) Flammability
B) Density
C) Reactivity with oxygen
D) Corrosiveness
Correct Answer: Density
Rationale: Density is a physical property because it can be measured without changing a
substance's chemical identity . Flammability, reactivity, and corrosiveness are chemical
properties because they describe how a substance undergoes a chemical change .
, 5. Which of the following describes a chemical change?
A) Ice melting into water
B) Water boiling
C) Iron rusting in moist air
D) Crushing aluminum foil
Correct Answer: Iron rusting in moist air
Rationale: Rusting is a chemical change because it forms a new substance, iron oxide .
Melting, boiling, and crushing are physical changes as they do not alter the chemical
composition of the matter.
6. A mixture of sand and iron filings is separated using a magnet. This separation technique is
possible because:
A) It is a homogeneous mixture
B) It is a compound
C) The iron filings are a pure substance with a unique physical property (magnetism)
D) It is a solution
Correct Answer: The iron filings are a pure substance with a unique physical property
(magnetism)
Rationale: The iron filings retain their physical property of being magnetic. This allows for a
physical separation from the sand, which is not magnetic, based on a difference in physical
properties.
7. Which SI unit is used to measure mass?
