SChemistry 10th Ed. Zumdahl Zumdahl DeCoste Chapters
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section 1: Chemical Foundations & Measurement (15 Questions)
Q1: A student measures the mass of a sample as 12.45 g, 12.43 g, and 12.46 g on three
successive trials. The actual mass is 15.20 g. These measurements are:
A. Accurate and precise
B. Precise but not accurate [CORRECT]
C. Accurate but not precise
D. Neither accurate nor precise
Correct Answer: B
Rationale: The measurements are close to each other (12.43–12.46 g), indicating
precision, but they are far from the true value (15.20 g), indicating inaccuracy; precision
refers to reproducibility, while accuracy refers to closeness to the true value (Zumdahl,
10th ed., Ch. 1).
Q2: How many significant figures are in the measurement 0.004050 m?
A. 3
B. 4 [CORRECT]
C. 5
D. 6
Correct Answer: B
Rationale: Leading zeros are not significant; the significant figures are 4, 0, 5, 0 (the
trailing zero after the decimal and after a significant digit is significant); thus there are 4
significant figures (Zumdahl, 10th ed., Ch. 1).
Q3: Convert 25.0°C to Kelvin.
A. 248.15 K
B. 298.15 K [CORRECT]
C. 273.15 K
D. 323.15 K
Correct Answer: B
Rationale: K = °C + 273.15; 25.0 + 273.15 = 298.15 K; this is the standard conversion
between Celsius and Kelvin temperature scales (Zumdahl, 10th ed., Ch. 1).
Q4: The density of a liquid is 1.25 g/mL. What is the mass of 45.0 mL of this liquid?
A. 36.0 g
,B. 56.3 g [CORRECT]
C. 45.0 g
D. 1.25 g
Correct Answer: B
Rationale: Density = mass/volume, so mass = density × volume = 1.25 g/mL × 45.0 mL =
56.25 g ≈ 56.3 g (rounded to 3 significant figures, matching the least precise
measurement) (Zumdahl, 10th ed., Ch. 1).
Q5: Express 0.0000456 in scientific notation.
A. 4.56 × 10⁻⁴
B. 4.56 × 10⁻⁵ [CORRECT]
C. 45.6 × 10⁻⁶
D. 0.456 × 10⁻⁴
Correct Answer: B
Rationale: Scientific notation requires one non-zero digit before the decimal point;
moving the decimal 5 places to the right gives 4.56 × 10⁻⁵; choice C is not proper
scientific notation (Zumdahl, 10th ed., Ch. 1).
Q6: A rectangular block measures 2.5 cm × 3.0 cm × 4.25 cm and has a mass of 127.5
g. What is its density?
A. 4.0 g/cm³ [CORRECT]
B. 4.00 g/cm³
C. 3.75 g/cm³
D. 5.0 g/cm³
Correct Answer: A
Rationale: Volume = 2.5 × 3.0 × 4.25 = 31.875 cm³; density = 127.5 g / 31.875 cm³ = 4.0
g/cm³ (rounded to 2 significant figures, matching the least precise measurement, 2.5
cm) (Zumdahl, 10th ed., Ch. 1).
Q7: Which SI prefix represents 10⁻³?
A. Micro (μ)
B. Milli (m) [CORRECT]
C. Centi (c)
D. Nano (n)
Correct Answer: B
Rationale: Milli (m) represents 10⁻³; micro (μ) = 10⁻⁶, centi (c) = 10⁻², and nano (n) = 10⁻⁹;
these prefixes are essential for metric system conversions (Zumdahl, 10th ed., Ch. 1).
Q8: A solution has a concentration of 2.50 × 10⁻⁴ M. Express this in micromolar (μM).
A. 0.250 μM
B. 2.50 μM
C. 250 μM [CORRECT]
D. 2500 μM
, Correct Answer: C
Rationale: 1 μM = 10⁻⁶ M; converting: 2.50 × 10⁻⁴ M × (1 μM / 10⁻⁶ M) = 2.50 × 10² μM =
250 μM; dimensional analysis ensures proper unit conversion (Zumdahl, 10th ed., Ch.
1).
Q9: The result of multiplying 2.34 cm × 1.2 cm should be reported as:
A. 2.808 cm²
B. 2.81 cm²
C. 2.8 cm² [CORRECT]
D. 3 cm²
Correct Answer: C
Rationale: In multiplication, the result is limited by the measurement with the fewest
significant figures; 1.2 cm has 2 significant figures, so the answer must be reported to 2
significant figures: 2.8 cm² (Zumdahl, 10th ed., Ch. 1).
Q10: A student performs a titration and obtains volumes of 24.85 mL, 24.90 mL, and
24.87 mL. The average volume should be reported as:
A. 24.873 mL
B. 24.87 mL [CORRECT]
C. 24.9 mL
D. 25 mL
Correct Answer: B
Rationale: Average = (24.85 + 24.90 + 24.87) / 3 = 74. = 24.8733... mL; all
measurements have 2 decimal places, so the average is reported to 2 decimal places:
24.87 mL (Zumdahl, 10th ed., Ch. 1).
Q11: What is the percent error if a student measures 5.20 g when the accepted value is
5.00 g?
A. 0.20%
B. 3.85%
C. 4.0% [CORRECT]
D. 20%
Correct Answer: C
Rationale: Percent error = |experimental - accepted| / accepted × 100 = |5.20 - 5.00| /
5.00 × 100 = 0..00 × 100 = 4.0%; this quantifies measurement accuracy (Zumdahl,
10th ed., Ch. 1).
Q12: Convert 2.5 L to milliliters.
A. 0.0025 mL
B. 25 mL
C. 250 mL
D. 2500 mL [CORRECT]
Correct Answer: D
1-22 Test Bank Actual Exam 2026/2027 – Comprehensive
Guide with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
section 1: Chemical Foundations & Measurement (15 Questions)
Q1: A student measures the mass of a sample as 12.45 g, 12.43 g, and 12.46 g on three
successive trials. The actual mass is 15.20 g. These measurements are:
A. Accurate and precise
B. Precise but not accurate [CORRECT]
C. Accurate but not precise
D. Neither accurate nor precise
Correct Answer: B
Rationale: The measurements are close to each other (12.43–12.46 g), indicating
precision, but they are far from the true value (15.20 g), indicating inaccuracy; precision
refers to reproducibility, while accuracy refers to closeness to the true value (Zumdahl,
10th ed., Ch. 1).
Q2: How many significant figures are in the measurement 0.004050 m?
A. 3
B. 4 [CORRECT]
C. 5
D. 6
Correct Answer: B
Rationale: Leading zeros are not significant; the significant figures are 4, 0, 5, 0 (the
trailing zero after the decimal and after a significant digit is significant); thus there are 4
significant figures (Zumdahl, 10th ed., Ch. 1).
Q3: Convert 25.0°C to Kelvin.
A. 248.15 K
B. 298.15 K [CORRECT]
C. 273.15 K
D. 323.15 K
Correct Answer: B
Rationale: K = °C + 273.15; 25.0 + 273.15 = 298.15 K; this is the standard conversion
between Celsius and Kelvin temperature scales (Zumdahl, 10th ed., Ch. 1).
Q4: The density of a liquid is 1.25 g/mL. What is the mass of 45.0 mL of this liquid?
A. 36.0 g
,B. 56.3 g [CORRECT]
C. 45.0 g
D. 1.25 g
Correct Answer: B
Rationale: Density = mass/volume, so mass = density × volume = 1.25 g/mL × 45.0 mL =
56.25 g ≈ 56.3 g (rounded to 3 significant figures, matching the least precise
measurement) (Zumdahl, 10th ed., Ch. 1).
Q5: Express 0.0000456 in scientific notation.
A. 4.56 × 10⁻⁴
B. 4.56 × 10⁻⁵ [CORRECT]
C. 45.6 × 10⁻⁶
D. 0.456 × 10⁻⁴
Correct Answer: B
Rationale: Scientific notation requires one non-zero digit before the decimal point;
moving the decimal 5 places to the right gives 4.56 × 10⁻⁵; choice C is not proper
scientific notation (Zumdahl, 10th ed., Ch. 1).
Q6: A rectangular block measures 2.5 cm × 3.0 cm × 4.25 cm and has a mass of 127.5
g. What is its density?
A. 4.0 g/cm³ [CORRECT]
B. 4.00 g/cm³
C. 3.75 g/cm³
D. 5.0 g/cm³
Correct Answer: A
Rationale: Volume = 2.5 × 3.0 × 4.25 = 31.875 cm³; density = 127.5 g / 31.875 cm³ = 4.0
g/cm³ (rounded to 2 significant figures, matching the least precise measurement, 2.5
cm) (Zumdahl, 10th ed., Ch. 1).
Q7: Which SI prefix represents 10⁻³?
A. Micro (μ)
B. Milli (m) [CORRECT]
C. Centi (c)
D. Nano (n)
Correct Answer: B
Rationale: Milli (m) represents 10⁻³; micro (μ) = 10⁻⁶, centi (c) = 10⁻², and nano (n) = 10⁻⁹;
these prefixes are essential for metric system conversions (Zumdahl, 10th ed., Ch. 1).
Q8: A solution has a concentration of 2.50 × 10⁻⁴ M. Express this in micromolar (μM).
A. 0.250 μM
B. 2.50 μM
C. 250 μM [CORRECT]
D. 2500 μM
, Correct Answer: C
Rationale: 1 μM = 10⁻⁶ M; converting: 2.50 × 10⁻⁴ M × (1 μM / 10⁻⁶ M) = 2.50 × 10² μM =
250 μM; dimensional analysis ensures proper unit conversion (Zumdahl, 10th ed., Ch.
1).
Q9: The result of multiplying 2.34 cm × 1.2 cm should be reported as:
A. 2.808 cm²
B. 2.81 cm²
C. 2.8 cm² [CORRECT]
D. 3 cm²
Correct Answer: C
Rationale: In multiplication, the result is limited by the measurement with the fewest
significant figures; 1.2 cm has 2 significant figures, so the answer must be reported to 2
significant figures: 2.8 cm² (Zumdahl, 10th ed., Ch. 1).
Q10: A student performs a titration and obtains volumes of 24.85 mL, 24.90 mL, and
24.87 mL. The average volume should be reported as:
A. 24.873 mL
B. 24.87 mL [CORRECT]
C. 24.9 mL
D. 25 mL
Correct Answer: B
Rationale: Average = (24.85 + 24.90 + 24.87) / 3 = 74. = 24.8733... mL; all
measurements have 2 decimal places, so the average is reported to 2 decimal places:
24.87 mL (Zumdahl, 10th ed., Ch. 1).
Q11: What is the percent error if a student measures 5.20 g when the accepted value is
5.00 g?
A. 0.20%
B. 3.85%
C. 4.0% [CORRECT]
D. 20%
Correct Answer: C
Rationale: Percent error = |experimental - accepted| / accepted × 100 = |5.20 - 5.00| /
5.00 × 100 = 0..00 × 100 = 4.0%; this quantifies measurement accuracy (Zumdahl,
10th ed., Ch. 1).
Q12: Convert 2.5 L to milliliters.
A. 0.0025 mL
B. 25 mL
C. 250 mL
D. 2500 mL [CORRECT]
Correct Answer: D
