,CHEM 121 Module 1 Exam Foundations of General
Chemistry w/Lab | Portage | 26/27 Actual (PDF)
1. Which of the following best defines the domain of chemistry that deals with the composition,
properties, and interactions of matter at the level of atoms and molecules?
A) Macroscopic domain
B) Microscopic domain
C) Symbolic domain
D) Thermodynamic domain
Correct Answer: Microscopic domain
Rationale: The microscopic domain focuses on the realm of atoms and molecules, explaining
phenomena at the particulate level. The macroscopic domain deals with ordinary-sized objects, the
symbolic domain uses symbols and equations, and thermodynamics is a subdiscipline. Options A, C,
and D incorrectly identify the domain.
2. A student records the following measurements for the density of a metal: 7.82, 7.85, and 7.83 g/mL.
The true density is 8.96 g/mL. Which statement best describes these measurements?
A) They are accurate but not precise.
B) They are precise but not accurate.
C) They are both accurate and precise.
D) They are neither accurate nor precise.
,Correct Answer: They are precise but not accurate.
Rationale: Precision refers to the closeness of repeated measurements to each other, while accuracy
refers to their closeness to the true value. The values are tightly clustered (precise) but far from 8.96
g/mL (not accurate). Options A, C, and D mischaracterize the data.
3. Which of the following represents a heterogeneous mixture?
A) Saltwater
B) Air
C) A suspension of sand in water
D) Brass
Correct Answer: A suspension of sand in water
Rationale: A heterogeneous mixture has non-uniform composition with visible phases, such as sand in
water. Saltwater, air, and brass are homogeneous mixtures (solutions) with uniform composition.
Options A, B, and D are incorrect.
4. What is the correct scientific notation for the number 0.0000456?
A) 4.56 × 10⁻⁵
B) 4.56 × 10⁻⁴
C) 4.56 × 10⁵
, D) 45.6 × 10⁻⁶
Correct Answer: 4.56 × 10⁻⁵
Rationale: To convert to scientific notation, move the decimal point right until one non-zero digit
remains: 0.0000456 → 4.56 × 10⁻⁵. Options B, C, and D have incorrect exponents or mantissa values.
5. How many significant figures are in the measurement 0.00520 g?
A) 2
B) 3
C) 4
D) 5
Correct Answer: 3
Rationale: Leading zeros are not significant. The digits 5, 2, and the trailing zero (after the decimal) are
significant, giving three significant figures. Options A, C, and D incorrectly count the leading zeros or
other digits.
6. Which of the following is an example of a chemical change?
A) Melting of ice
B) Dissolving sugar in water
Chemistry w/Lab | Portage | 26/27 Actual (PDF)
1. Which of the following best defines the domain of chemistry that deals with the composition,
properties, and interactions of matter at the level of atoms and molecules?
A) Macroscopic domain
B) Microscopic domain
C) Symbolic domain
D) Thermodynamic domain
Correct Answer: Microscopic domain
Rationale: The microscopic domain focuses on the realm of atoms and molecules, explaining
phenomena at the particulate level. The macroscopic domain deals with ordinary-sized objects, the
symbolic domain uses symbols and equations, and thermodynamics is a subdiscipline. Options A, C,
and D incorrectly identify the domain.
2. A student records the following measurements for the density of a metal: 7.82, 7.85, and 7.83 g/mL.
The true density is 8.96 g/mL. Which statement best describes these measurements?
A) They are accurate but not precise.
B) They are precise but not accurate.
C) They are both accurate and precise.
D) They are neither accurate nor precise.
,Correct Answer: They are precise but not accurate.
Rationale: Precision refers to the closeness of repeated measurements to each other, while accuracy
refers to their closeness to the true value. The values are tightly clustered (precise) but far from 8.96
g/mL (not accurate). Options A, C, and D mischaracterize the data.
3. Which of the following represents a heterogeneous mixture?
A) Saltwater
B) Air
C) A suspension of sand in water
D) Brass
Correct Answer: A suspension of sand in water
Rationale: A heterogeneous mixture has non-uniform composition with visible phases, such as sand in
water. Saltwater, air, and brass are homogeneous mixtures (solutions) with uniform composition.
Options A, B, and D are incorrect.
4. What is the correct scientific notation for the number 0.0000456?
A) 4.56 × 10⁻⁵
B) 4.56 × 10⁻⁴
C) 4.56 × 10⁵
, D) 45.6 × 10⁻⁶
Correct Answer: 4.56 × 10⁻⁵
Rationale: To convert to scientific notation, move the decimal point right until one non-zero digit
remains: 0.0000456 → 4.56 × 10⁻⁵. Options B, C, and D have incorrect exponents or mantissa values.
5. How many significant figures are in the measurement 0.00520 g?
A) 2
B) 3
C) 4
D) 5
Correct Answer: 3
Rationale: Leading zeros are not significant. The digits 5, 2, and the trailing zero (after the decimal) are
significant, giving three significant figures. Options A, C, and D incorrectly count the leading zeros or
other digits.
6. Which of the following is an example of a chemical change?
A) Melting of ice
B) Dissolving sugar in water
