CHEM 103 MIDTERM 1 COMPLETE TEST
BANK (UNLV) SOLVED MCQS FOR
EXAM SUCCESS
Master your first college chemistry exam with this comprehensive practice
bank specifically engineered for UNLV General Chemistry students. Each
multiple-choice question features highlighted answers and in-depth, bolded
analytical rationales that break down complex dimensional analysis,
nomenclature, and stoichiometry concepts into clear, digestible steps. It
serves as an all-in-one midterm study companion designed to build testing
confidence and guarantee a top grade on your upcoming exam.
Module 1: Matter, Measurements, and
Mathematical Tools
1. Which of the following is classified as a
homogeneous mixture?
A) Distilled water
B) Carbon dioxide gas
C) Clean tap water
D) A bowl of cereal with milk
Answer: C
Rationale: Clean tap water contains dissolved
minerals uniformly distributed throughout the
liquid, making it a homogeneous mixture
(solution). Distilled water and carbon dioxide are
pure substances, while cereal in milk is a
heterogeneous mixture.
,2. A block of an unknown metal has a mass of
125.0 g and measures 2.50 cm by 3.00 cm by
2.00 cm. What is the density of the metal?
A) 8.33 g/cm³
B) 0.120 g/cm³
C) 15.0 g/cm³
D) 4.17 g/cm³
Answer: A
Rationale: Volume = length × width × height =
2.50 cm × 3.00 cm × 2.00 cm = 15.0 cm³. Density
= mass / volume = 125.0 g / 15.0 cm³ = 8.33
g/cm³.
3. Express the measurement 0.000450 meters in
standard scientific notation with the correct
number of significant figures.
A) 4.5 × 10⁻⁴ m
B) 4.50 × 10⁻⁴ m
C) 4.50 × 10⁴ m
D) 4.5 × 10⁻³ m
Answer: B
Rationale: The original number has three
significant figures (the trailing zero counts
because there is a decimal point). Moving the
decimal point 4 places to the right yields 4.50 ×
10⁻⁴ m.
,4. Perform the following calculation and report
the answer to the correct number of significant
figures: 102.15 + 12.3 - 4.556
A) 109.894
B) 109.9
C) 110
D) 109.89
Answer: B
Rationale: For addition and subtraction, the
result is limited by the value with the fewest
decimal places. 12.3 has only one decimal place,
so the final answer must be rounded to one
decimal place (109.894 rounds to 109.9).
5. How many significant figures are in the value
4.050 × 10³?
A) 2
B) 3
C) 4
D) 5
Answer: C
Rationale: In scientific notation, all digits in the
coefficient are significant. Both the captive zero
and the trailing zero count, giving a total of 4
significant figures.
, 6. Perform the following operation and report the
answer to the correct number of significant
figures: (2.50 × 4.0) / 1.234
A) 8.1
B) 8.10
C) 8.104
D) 8
Answer: A
Rationale: For multiplication and division, the
result is limited by the term with the fewest total
significant figures. The term 4.0 has two
significant figures, so the answer must be
rounded to two significant figures (8.1037
rounds to 8.1).
7. A laboratory analyst measures the boiling
point of pure water to be 95.2°C, 95.1°C, and
95.3°C. The true boiling point is 100.0°C. This
dataset is:
A) Both accurate and precise
B) Accurate but not precise
C) Precise but not accurate
D) Neither accurate nor precise
Answer: C
Rationale: The measurements are close to one
another (high precision) but far from the true
BANK (UNLV) SOLVED MCQS FOR
EXAM SUCCESS
Master your first college chemistry exam with this comprehensive practice
bank specifically engineered for UNLV General Chemistry students. Each
multiple-choice question features highlighted answers and in-depth, bolded
analytical rationales that break down complex dimensional analysis,
nomenclature, and stoichiometry concepts into clear, digestible steps. It
serves as an all-in-one midterm study companion designed to build testing
confidence and guarantee a top grade on your upcoming exam.
Module 1: Matter, Measurements, and
Mathematical Tools
1. Which of the following is classified as a
homogeneous mixture?
A) Distilled water
B) Carbon dioxide gas
C) Clean tap water
D) A bowl of cereal with milk
Answer: C
Rationale: Clean tap water contains dissolved
minerals uniformly distributed throughout the
liquid, making it a homogeneous mixture
(solution). Distilled water and carbon dioxide are
pure substances, while cereal in milk is a
heterogeneous mixture.
,2. A block of an unknown metal has a mass of
125.0 g and measures 2.50 cm by 3.00 cm by
2.00 cm. What is the density of the metal?
A) 8.33 g/cm³
B) 0.120 g/cm³
C) 15.0 g/cm³
D) 4.17 g/cm³
Answer: A
Rationale: Volume = length × width × height =
2.50 cm × 3.00 cm × 2.00 cm = 15.0 cm³. Density
= mass / volume = 125.0 g / 15.0 cm³ = 8.33
g/cm³.
3. Express the measurement 0.000450 meters in
standard scientific notation with the correct
number of significant figures.
A) 4.5 × 10⁻⁴ m
B) 4.50 × 10⁻⁴ m
C) 4.50 × 10⁴ m
D) 4.5 × 10⁻³ m
Answer: B
Rationale: The original number has three
significant figures (the trailing zero counts
because there is a decimal point). Moving the
decimal point 4 places to the right yields 4.50 ×
10⁻⁴ m.
,4. Perform the following calculation and report
the answer to the correct number of significant
figures: 102.15 + 12.3 - 4.556
A) 109.894
B) 109.9
C) 110
D) 109.89
Answer: B
Rationale: For addition and subtraction, the
result is limited by the value with the fewest
decimal places. 12.3 has only one decimal place,
so the final answer must be rounded to one
decimal place (109.894 rounds to 109.9).
5. How many significant figures are in the value
4.050 × 10³?
A) 2
B) 3
C) 4
D) 5
Answer: C
Rationale: In scientific notation, all digits in the
coefficient are significant. Both the captive zero
and the trailing zero count, giving a total of 4
significant figures.
, 6. Perform the following operation and report the
answer to the correct number of significant
figures: (2.50 × 4.0) / 1.234
A) 8.1
B) 8.10
C) 8.104
D) 8
Answer: A
Rationale: For multiplication and division, the
result is limited by the term with the fewest total
significant figures. The term 4.0 has two
significant figures, so the answer must be
rounded to two significant figures (8.1037
rounds to 8.1).
7. A laboratory analyst measures the boiling
point of pure water to be 95.2°C, 95.1°C, and
95.3°C. The true boiling point is 100.0°C. This
dataset is:
A) Both accurate and precise
B) Accurate but not precise
C) Precise but not accurate
D) Neither accurate nor precise
Answer: C
Rationale: The measurements are close to one
another (high precision) but far from the true
