,Chapter 1: Chemical Foundations
Topics covered: Scientific method, units of measurement, significant
figures, uncertainty, classification of matter, and properties of
substances.
1. Which of the following best exemplifies a hypothesis in the
scientific method?
A. The law of conservation of mass
B. Matter is made of atoms
C. If salt is added to water, the boiling point will increase
D. Water is composed of hydrogen and oxygen
✅ Correct Answer: C. If salt is added to water, the boiling point will
increase
Rationale: A hypothesis is a testable, tentative explanation or
prediction. Option C proposes a specific outcome that can be
experimentally tested, fulfilling the criteria of a hypothesis.
2. Which of the following SI base units is incorrectly matched with
its quantity?
A. Kilogram – mass
B. Kelvin – temperature
C. Ampere – electric current
D. Liter – volume
✅ Correct Answer: D. Liter – volume
Rationale: While the liter is commonly used, it is a derived unit, not a
base unit. The SI base unit for volume is cubic meters (m³). All others
listed are official SI base units.
,3. Which measurement expresses the highest precision?
A. 6.4 m
B. 6.400 m
C. 6 m
D. 6.40 m
✅ Correct Answer: B. 6.400 m
Rationale: Precision is indicated by the number of significant figures.
"6.400" has four significant figures, the most of the options given,
implying the highest precision.
4. Which type of error consistently skews data in one direction?
A. Random error
B. Systematic error
C. Instrumental fluctuation
D. Statistical error
✅ Correct Answer: B. Systematic error
Rationale: Systematic errors affect all measurements in a predictable
direction due to instrument calibration or procedural bias, leading to
inaccurate but precise data.
5. Which of the following best distinguishes a compound from a
mixture?
A. A compound is homogeneous, a mixture is not
B. A compound has variable composition
C. A compound has elements in fixed ratios by mass
D. A mixture cannot be separated physically
, ✅ Correct Answer: C. A compound has elements in fixed ratios by
mass
Rationale: Compounds have definite chemical composition governed by
chemical formulas. Mixtures can have variable ratios and be separated
physically.
6. Which pair represents a physical property and a chemical
property, respectively?
A. Boiling point, density
B. Solubility, malleability
C. Mass, combustibility
D. Ductility, odor
✅ Correct Answer: C. Mass, combustibility
Rationale: Physical properties (e.g., mass) do not alter the substance's
identity. Chemical properties (e.g., combustibility) describe reactivity
and involve chemical change.
7. Which process represents a chemical change?
A. Ice melting
B. Sugar dissolving in water
C. Iron rusting
D. Water boiling
✅ Correct Answer: C. Iron rusting
Rationale: Rusting involves oxidation and the formation of a new
substance (iron oxide), qualifying it as a chemical change. The others are
physical changes.
Topics covered: Scientific method, units of measurement, significant
figures, uncertainty, classification of matter, and properties of
substances.
1. Which of the following best exemplifies a hypothesis in the
scientific method?
A. The law of conservation of mass
B. Matter is made of atoms
C. If salt is added to water, the boiling point will increase
D. Water is composed of hydrogen and oxygen
✅ Correct Answer: C. If salt is added to water, the boiling point will
increase
Rationale: A hypothesis is a testable, tentative explanation or
prediction. Option C proposes a specific outcome that can be
experimentally tested, fulfilling the criteria of a hypothesis.
2. Which of the following SI base units is incorrectly matched with
its quantity?
A. Kilogram – mass
B. Kelvin – temperature
C. Ampere – electric current
D. Liter – volume
✅ Correct Answer: D. Liter – volume
Rationale: While the liter is commonly used, it is a derived unit, not a
base unit. The SI base unit for volume is cubic meters (m³). All others
listed are official SI base units.
,3. Which measurement expresses the highest precision?
A. 6.4 m
B. 6.400 m
C. 6 m
D. 6.40 m
✅ Correct Answer: B. 6.400 m
Rationale: Precision is indicated by the number of significant figures.
"6.400" has four significant figures, the most of the options given,
implying the highest precision.
4. Which type of error consistently skews data in one direction?
A. Random error
B. Systematic error
C. Instrumental fluctuation
D. Statistical error
✅ Correct Answer: B. Systematic error
Rationale: Systematic errors affect all measurements in a predictable
direction due to instrument calibration or procedural bias, leading to
inaccurate but precise data.
5. Which of the following best distinguishes a compound from a
mixture?
A. A compound is homogeneous, a mixture is not
B. A compound has variable composition
C. A compound has elements in fixed ratios by mass
D. A mixture cannot be separated physically
, ✅ Correct Answer: C. A compound has elements in fixed ratios by
mass
Rationale: Compounds have definite chemical composition governed by
chemical formulas. Mixtures can have variable ratios and be separated
physically.
6. Which pair represents a physical property and a chemical
property, respectively?
A. Boiling point, density
B. Solubility, malleability
C. Mass, combustibility
D. Ductility, odor
✅ Correct Answer: C. Mass, combustibility
Rationale: Physical properties (e.g., mass) do not alter the substance's
identity. Chemical properties (e.g., combustibility) describe reactivity
and involve chemical change.
7. Which process represents a chemical change?
A. Ice melting
B. Sugar dissolving in water
C. Iron rusting
D. Water boiling
✅ Correct Answer: C. Iron rusting
Rationale: Rusting involves oxidation and the formation of a new
substance (iron oxide), qualifying it as a chemical change. The others are
physical changes.
