1
CHEM 103 FINAL EXAM 2026/2027 | Comprehensive
General Chemistry | Portage Learning | 100% Verified
Elaborations | 100 out of 100 Score | Pass Guaranteed - A+
Graded
[Section 1: Measurement, Units & Dimensional Analysis (Q1-12)]
Q1. Which of the following is the correct SI base unit for the amount of substance?
A. Gram B. Liter C. Mole [CORRECT] D. Kilogram
Correct Answer: C
Rationale: The mole (mol) is the SI base unit for amount of substance, defined as
exactly 6.02214076×10²³ elementary entities. The gram is a metric unit of mass but
not an SI base unit; the liter is a derived unit for volume; the kilogram is the SI base
unit for mass.
Q2. Convert 2.50 kilometers into millimeters.
A. 2.50×10³ mm B. 2.50×10⁴ mm C. 2.50×10⁶ mm [CORRECT] D. 2.50×10⁻³ mm
Correct Answer: C
Rationale: Using dimensional analysis: 2.50 km × (10³ m/1 km) × (10³ mm/1 m) =
2.50×10⁶ mm. The metric prefix conversion requires multiplying by 10³ to reach
meters and another 10³ to reach millimeters, giving 10⁶ total.
Q3. How many significant figures are in the measurement 0.004050?
A. 3 B. 4 [CORRECT] C. 5 D. 6
,2
Correct Answer: B
Rationale: Leading zeros (0.00) are not significant; captive zeros (4050) are
significant; the trailing zero after the decimal (4050.) is significant. Thus, 4, 0, 5, 0 are
significant = 4 significant figures. Students often miss that the trailing zero in a
decimal number is significant.
Q4. A student adds three measurements: 12.11 mL + 18.0 mL + 1.013 mL. What is the
correct sum respecting significant figures?
A. 31.123 mL B. 31.12 mL C. 31.1 mL [CORRECT] D. 31 mL
Correct Answer: C
Rationale: For addition/subtraction, the result is rounded to the least number of
decimal places. 18.0 has one decimal place (tenths), so the sum 31.123 must be
rounded to the tenths place: 31.1 mL. Students often incorrectly apply multiplication
sig fig rules to addition.
Q5. Express the number 0.000456 in proper scientific notation.
A. 456×10⁻⁶ B. 45.6×10⁻⁵ C. 4.56×10⁻⁴ [CORRECT] D. 0.456×10⁻³
Correct Answer: C
Rationale: Proper scientific notation requires a coefficient between 1 and 10
multiplied by a power of 10. Moving the decimal four places to the right gives
4.56×10⁻⁴. Options A and B have coefficients outside the 1–10 range, violating
scientific notation format.
Q6. A car travels at a speed of 25.0 meters per second. What is its speed in
kilometers per hour?
A. 6.94 km/hr B. 15.5 km/hr C. 90.0 km/hr [CORRECT] D. 150 km/hr
,3
Correct Answer: C
Rationale: Dimensional analysis: 25.0 m/s × (1 km/1000 m) × (3600 s/1 hr) = 90.0
km/hr. The conversion factors 1000 m = 1 km and 3600 s = 1 hr must both be
applied; common errors include omitting one factor or misplacing the ratio.
Q7. A fever thermometer reads 102.0°F. What is this temperature in degrees Celsius?
A. 38.9°C [CORRECT] B. 40.0°C C. 212°C D. 312°C
Correct Answer: A
Rationale: Using °C = (°F − 32)/1.8: (102.0 − 32)/1.8 = 70.0/1.8 = 38.9°C. Common
errors include using °C = °F − 32 (forgetting to divide by 1.8) or incorrectly
multiplying instead of dividing.
Q8. A metal block has a mass of 45.0 g and occupies a volume of 15.0 mL. What is its
density?
A. 0.333 g/mL B. 3.00 g/mL [CORRECT] C. 30.0 g/mL D. 675 g/mL
Correct Answer: B
Rationale: Density = mass/volume = 45.0 g/15.0 mL = 3.00 g/mL. Distractor A
results from dividing volume by mass (inverted), while D results from multiplying
mass × volume instead of dividing.
Q9. A liquid has a density of 2.50 g/mL at 4°C. What is its specific gravity?
A. 0.250 B. 2.50 [CORRECT] C. 25.0 D. 0.400
Correct Answer: B
, 4
Rationale: Specific gravity = density of substance/density of water at 4°C = 2.50
g/mL ÷ 1.00 g/mL = 2.50 (dimensionless). Because water's density is 1.00 g/mL at
4°C, the numerical value equals the density in g/mL, but specific gravity has no units.
Q10. A student experimentally determines the mass of a sample to be 12.0 g, but the
accepted value is 12.5 g. What is the percent error?
A. 2.50% B. 4.00% [CORRECT] C. 5.00% D. 8.33%
Correct Answer: B
Rationale: Percent error = |experimental − theoretical|/theoretical × 100% = |12.0 −
12.5|/12.5 × 100% = 0.5/12.5 × 100% = 4.00%. Distractor C arises from dividing by
the experimental value (0.5/12.0 × 100%), which is the incorrect formula.
Q11. A buret reading is recorded as 25.50 mL. How many significant figures does this
measurement contain?
A. 2 B. 3 C. 4 [CORRECT] D. 5
Correct Answer: C
Rationale: Burets are calibrated to deliver and are read to two decimal places (±0.01
mL precision); 25.50 mL has four significant figures. The trailing zero after the
decimal is significant because it indicates the precision of the measurement
instrument.
Q12. How many liters are in 450. mL?
A. 0.0450 L B. 0.450 L [CORRECT] C. 4.50 L D. 450,000 L
Correct Answer: B
CHEM 103 FINAL EXAM 2026/2027 | Comprehensive
General Chemistry | Portage Learning | 100% Verified
Elaborations | 100 out of 100 Score | Pass Guaranteed - A+
Graded
[Section 1: Measurement, Units & Dimensional Analysis (Q1-12)]
Q1. Which of the following is the correct SI base unit for the amount of substance?
A. Gram B. Liter C. Mole [CORRECT] D. Kilogram
Correct Answer: C
Rationale: The mole (mol) is the SI base unit for amount of substance, defined as
exactly 6.02214076×10²³ elementary entities. The gram is a metric unit of mass but
not an SI base unit; the liter is a derived unit for volume; the kilogram is the SI base
unit for mass.
Q2. Convert 2.50 kilometers into millimeters.
A. 2.50×10³ mm B. 2.50×10⁴ mm C. 2.50×10⁶ mm [CORRECT] D. 2.50×10⁻³ mm
Correct Answer: C
Rationale: Using dimensional analysis: 2.50 km × (10³ m/1 km) × (10³ mm/1 m) =
2.50×10⁶ mm. The metric prefix conversion requires multiplying by 10³ to reach
meters and another 10³ to reach millimeters, giving 10⁶ total.
Q3. How many significant figures are in the measurement 0.004050?
A. 3 B. 4 [CORRECT] C. 5 D. 6
,2
Correct Answer: B
Rationale: Leading zeros (0.00) are not significant; captive zeros (4050) are
significant; the trailing zero after the decimal (4050.) is significant. Thus, 4, 0, 5, 0 are
significant = 4 significant figures. Students often miss that the trailing zero in a
decimal number is significant.
Q4. A student adds three measurements: 12.11 mL + 18.0 mL + 1.013 mL. What is the
correct sum respecting significant figures?
A. 31.123 mL B. 31.12 mL C. 31.1 mL [CORRECT] D. 31 mL
Correct Answer: C
Rationale: For addition/subtraction, the result is rounded to the least number of
decimal places. 18.0 has one decimal place (tenths), so the sum 31.123 must be
rounded to the tenths place: 31.1 mL. Students often incorrectly apply multiplication
sig fig rules to addition.
Q5. Express the number 0.000456 in proper scientific notation.
A. 456×10⁻⁶ B. 45.6×10⁻⁵ C. 4.56×10⁻⁴ [CORRECT] D. 0.456×10⁻³
Correct Answer: C
Rationale: Proper scientific notation requires a coefficient between 1 and 10
multiplied by a power of 10. Moving the decimal four places to the right gives
4.56×10⁻⁴. Options A and B have coefficients outside the 1–10 range, violating
scientific notation format.
Q6. A car travels at a speed of 25.0 meters per second. What is its speed in
kilometers per hour?
A. 6.94 km/hr B. 15.5 km/hr C. 90.0 km/hr [CORRECT] D. 150 km/hr
,3
Correct Answer: C
Rationale: Dimensional analysis: 25.0 m/s × (1 km/1000 m) × (3600 s/1 hr) = 90.0
km/hr. The conversion factors 1000 m = 1 km and 3600 s = 1 hr must both be
applied; common errors include omitting one factor or misplacing the ratio.
Q7. A fever thermometer reads 102.0°F. What is this temperature in degrees Celsius?
A. 38.9°C [CORRECT] B. 40.0°C C. 212°C D. 312°C
Correct Answer: A
Rationale: Using °C = (°F − 32)/1.8: (102.0 − 32)/1.8 = 70.0/1.8 = 38.9°C. Common
errors include using °C = °F − 32 (forgetting to divide by 1.8) or incorrectly
multiplying instead of dividing.
Q8. A metal block has a mass of 45.0 g and occupies a volume of 15.0 mL. What is its
density?
A. 0.333 g/mL B. 3.00 g/mL [CORRECT] C. 30.0 g/mL D. 675 g/mL
Correct Answer: B
Rationale: Density = mass/volume = 45.0 g/15.0 mL = 3.00 g/mL. Distractor A
results from dividing volume by mass (inverted), while D results from multiplying
mass × volume instead of dividing.
Q9. A liquid has a density of 2.50 g/mL at 4°C. What is its specific gravity?
A. 0.250 B. 2.50 [CORRECT] C. 25.0 D. 0.400
Correct Answer: B
, 4
Rationale: Specific gravity = density of substance/density of water at 4°C = 2.50
g/mL ÷ 1.00 g/mL = 2.50 (dimensionless). Because water's density is 1.00 g/mL at
4°C, the numerical value equals the density in g/mL, but specific gravity has no units.
Q10. A student experimentally determines the mass of a sample to be 12.0 g, but the
accepted value is 12.5 g. What is the percent error?
A. 2.50% B. 4.00% [CORRECT] C. 5.00% D. 8.33%
Correct Answer: B
Rationale: Percent error = |experimental − theoretical|/theoretical × 100% = |12.0 −
12.5|/12.5 × 100% = 0.5/12.5 × 100% = 4.00%. Distractor C arises from dividing by
the experimental value (0.5/12.0 × 100%), which is the incorrect formula.
Q11. A buret reading is recorded as 25.50 mL. How many significant figures does this
measurement contain?
A. 2 B. 3 C. 4 [CORRECT] D. 5
Correct Answer: C
Rationale: Burets are calibrated to deliver and are read to two decimal places (±0.01
mL precision); 25.50 mL has four significant figures. The trailing zero after the
decimal is significant because it indicates the precision of the measurement
instrument.
Q12. How many liters are in 450. mL?
A. 0.0450 L B. 0.450 L [CORRECT] C. 4.50 L D. 450,000 L
Correct Answer: B
