CHEM 103 General Chemistry I with Lab
ACTUAL EXAM [2026] | Lab Questions |
Verified Q&A | Pass Guaranteed - A+
Graded
SECTION 1: Measurement, Units & Dimensional Analysis (8 Questions)
Q1: A student measures a liquid volume as 25.0 mL and mass as 33.25 g. What is the
density reported with the correct number of significant figures?
A. 1.3 g/mL
B. 1.33 g/mL
C. 1.330 g/mL
D. 1.3300 g/mL
Correct Answer: B
Rationale: Density equals mass divided by volume: 33.25 g ÷ 25.0 mL = 1.33 g/mL. The
value 25.0 mL has three significant figures, so the final answer must be reported to
three significant figures.
Q2: Convert 4.52 × 10⁻³ km to millimeters.
,A. 4.52 mm
B. 45.2 mm
C. 452 mm
D. 4520 mm
Correct Answer: D
Rationale: One kilometer equals 10⁶ millimeters. Therefore, 4.52 × 10⁻³ km × 10⁶
mm/km = 4.52 × 10³ mm = 4520 mm.
Q3: A rectangular metal block measures 2.50 cm × 3.00 cm × 4.20 cm and has a mass
of 189.0 g. The density of the metal is:
A. 5.0 g/cm³
B. 6.00 g/cm³
C. 6.0 g/cm³
D. 5.00 g/cm³
Correct Answer: B
Rationale: Volume equals 2.50 cm × 3.00 cm × 4.20 cm = 31.5 cm³. Density equals
189.0 g ÷ 31.5 cm³ = 6.00 g/cm³. All measurements have three significant figures, so
the answer is reported to three significant figures.
Q4: How many micrograms are in 2.50 × 10⁻⁴ grams?
A. 2.50 × 10⁻¹⁰ μg
,B. 2.50 × 10⁻¹ μg
C. 2.50 × 10² μg
D. 2.50 × 10⁵ μg
Correct Answer: C
Rationale: One gram equals 10⁶ micrograms. Therefore, 2.50 × 10⁻⁴ g × 10⁶ μg/g = 2.50
× 10² μg = 250 μg.
Q5: A student measures the boiling point of a liquid five times and obtains values of
98.2°C, 98.5°C, 98.3°C, 98.4°C, and 98.3°C. The literature value is 100.0°C. These
measurements are:
A. Accurate but not precise
B. Precise but not accurate
C. Both accurate and precise
D. Neither accurate nor precise
Correct Answer: B
Rationale: The measurements are clustered closely together (within 0.3°C),
demonstrating precision. However, they deviate systematically from the true value of
100.0°C, indicating a lack of accuracy likely due to a systematic error such as a
miscalibrated thermometer.
Q6: Express 0.0000456 in scientific notation with three significant figures.
A. 4.56 × 10⁻⁵
, B. 4.55 × 10⁻⁵
C. 4.56 × 10⁵
D. 45.6 × 10⁻⁶
Correct Answer: A
Rationale: Scientific notation requires one nonzero digit to the left of the decimal point.
Moving the decimal point five places to the right yields 4.56 × 10⁻⁵, which retains three
significant figures.
Q7: A student calculates the percent error for an experiment using the formula
|experimental - accepted| ÷ |accepted| × 100%. The experimental value is 15.2 g and the
accepted value is 14.8 g. The percent error is:
A. 2.6%
B. 2.70%
C. 3%
D. 2.7%
Correct Answer: D
Rationale: Percent error equals |15.2 - 14.8| ÷ 14.8 × 100% = 0.4 ÷ 14.8 × 100% =
2.7027%. Since both values have three significant figures, the answer is reported as
2.7%.
Q8: Which measurement has the greatest precision based on the number of decimal
places recorded?
ACTUAL EXAM [2026] | Lab Questions |
Verified Q&A | Pass Guaranteed - A+
Graded
SECTION 1: Measurement, Units & Dimensional Analysis (8 Questions)
Q1: A student measures a liquid volume as 25.0 mL and mass as 33.25 g. What is the
density reported with the correct number of significant figures?
A. 1.3 g/mL
B. 1.33 g/mL
C. 1.330 g/mL
D. 1.3300 g/mL
Correct Answer: B
Rationale: Density equals mass divided by volume: 33.25 g ÷ 25.0 mL = 1.33 g/mL. The
value 25.0 mL has three significant figures, so the final answer must be reported to
three significant figures.
Q2: Convert 4.52 × 10⁻³ km to millimeters.
,A. 4.52 mm
B. 45.2 mm
C. 452 mm
D. 4520 mm
Correct Answer: D
Rationale: One kilometer equals 10⁶ millimeters. Therefore, 4.52 × 10⁻³ km × 10⁶
mm/km = 4.52 × 10³ mm = 4520 mm.
Q3: A rectangular metal block measures 2.50 cm × 3.00 cm × 4.20 cm and has a mass
of 189.0 g. The density of the metal is:
A. 5.0 g/cm³
B. 6.00 g/cm³
C. 6.0 g/cm³
D. 5.00 g/cm³
Correct Answer: B
Rationale: Volume equals 2.50 cm × 3.00 cm × 4.20 cm = 31.5 cm³. Density equals
189.0 g ÷ 31.5 cm³ = 6.00 g/cm³. All measurements have three significant figures, so
the answer is reported to three significant figures.
Q4: How many micrograms are in 2.50 × 10⁻⁴ grams?
A. 2.50 × 10⁻¹⁰ μg
,B. 2.50 × 10⁻¹ μg
C. 2.50 × 10² μg
D. 2.50 × 10⁵ μg
Correct Answer: C
Rationale: One gram equals 10⁶ micrograms. Therefore, 2.50 × 10⁻⁴ g × 10⁶ μg/g = 2.50
× 10² μg = 250 μg.
Q5: A student measures the boiling point of a liquid five times and obtains values of
98.2°C, 98.5°C, 98.3°C, 98.4°C, and 98.3°C. The literature value is 100.0°C. These
measurements are:
A. Accurate but not precise
B. Precise but not accurate
C. Both accurate and precise
D. Neither accurate nor precise
Correct Answer: B
Rationale: The measurements are clustered closely together (within 0.3°C),
demonstrating precision. However, they deviate systematically from the true value of
100.0°C, indicating a lack of accuracy likely due to a systematic error such as a
miscalibrated thermometer.
Q6: Express 0.0000456 in scientific notation with three significant figures.
A. 4.56 × 10⁻⁵
, B. 4.55 × 10⁻⁵
C. 4.56 × 10⁵
D. 45.6 × 10⁻⁶
Correct Answer: A
Rationale: Scientific notation requires one nonzero digit to the left of the decimal point.
Moving the decimal point five places to the right yields 4.56 × 10⁻⁵, which retains three
significant figures.
Q7: A student calculates the percent error for an experiment using the formula
|experimental - accepted| ÷ |accepted| × 100%. The experimental value is 15.2 g and the
accepted value is 14.8 g. The percent error is:
A. 2.6%
B. 2.70%
C. 3%
D. 2.7%
Correct Answer: D
Rationale: Percent error equals |15.2 - 14.8| ÷ 14.8 × 100% = 0.4 ÷ 14.8 × 100% =
2.7027%. Since both values have three significant figures, the answer is reported as
2.7%.
Q8: Which measurement has the greatest precision based on the number of decimal
places recorded?
