CHEM 120 WEEK 8 FINAL EXAM 2026/2027 | Solved Q&A |
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SECTION 1: Matter, Measurement & Unit Conversions (Q1–Q10)
Q1: A nurse needs to administer 0.250 g of a medication, but the syringe is marked in
milligrams. How many milligrams should the nurse draw up?
A. 2.50 mg
B. 25.0 mg
C. 250 mg [CORRECT]
D. 2500 mg
Correct Answer: C
Rationale: Since 1 g = 1000 mg, 0.250 g × 1000 = 250 mg. Option A incorrectly shifts the
decimal one place, B shifts it two places, and D multiplies by 10,000. Accurate metric
conversions are essential in clinical dosing to prevent medication errors.
Q2: Express the number 0.004560 in scientific notation with the correct number of
significant figures.
A. 4.56 × 10⁻³
B. 4.560 × 10⁻³ [CORRECT]
C. 4.5600 × 10⁻³
D. 4560 × 10⁻⁶
Correct Answer: B
Rationale: The leading zeros are not significant, but the trailing zero after the decimal is
significant, giving four significant figures. Option A drops the significant trailing zero.
Option C adds an extra insignificant zero. Option D is not proper scientific notation and
obscures significant figures.
Q3: The density of a saline solution is 1.025 g/mL. What is the mass of 500.0 mL of this
solution?
A. 488.0 g
,B. 512.5 g [CORRECT]
C. 487.8 g
D. 2.050 g
Correct Answer: B
Rationale: Using density = mass/volume, mass = 1.025 g/mL × 500.0 mL = 512.5 g.
Option A incorrectly divides density by volume. Option C inverts the density value.
Option D doubles the density without multiplying by volume. Density calculations are
critical for preparing IV solutions.
Q4: Which of the following represents a physical change rather than a chemical change?
A. Rusting of iron
B. Digestion of food
C. Dissolving sugar in water [CORRECT]
D. Burning of gasoline
Correct Answer: C
Rationale: Dissolving sugar is a physical change because the sugar molecules remain
intact and can be recovered by evaporation. Rusting, digestion, and combustion all
involve chemical reactions that alter molecular composition. Distinguishing physical
and chemical changes is foundational for understanding drug stability and metabolism.
Q5: A patient weighs 154 lbs. What is their mass in kilograms? (1 lb = 0.4536 kg)
A. 34.0 kg
B. 68.0 kg
C. 70.0 kg [CORRECT]
D. 339 kg
Correct Answer: C
Rationale: 154 lbs × 0.4536 kg/lb = 69.85 kg, which rounds to 70.0 kg. Option A uses an
incorrect conversion factor. Option B uses approximately 0.44 kg/lb. Option D divides by
0.4536 instead of multiplying. Weight-to-mass conversions are routine in calculating
drug dosages per kg body weight.
Q6: How many significant figures are in the measurement 0.003020 m?
A. 3
B. 4 [CORRECT]
C. 6
,D. 7
Correct Answer: B
Rationale: Leading zeros are not significant; the digits 3, 0, 2, and the trailing zero after
the decimal are significant, giving four significant figures. Option A misses the trailing
zero. Option C counts leading zeros. Option D counts all zeros. Significant figures
ensure precision in laboratory measurements and clinical diagnostics.
Q7: A clinical laboratory measures a blood volume as 4.50 × 10³ mL. What is this
volume in liters?
A. 0.450 L
B. 4.50 L [CORRECT]
C. 45.0 L
D. 450 L
Correct Answer: B
Rationale: 4.50 × 10³ mL = 4500 mL. Dividing by 1000 mL/L gives 4.50 L. Option A
incorrectly shifts the decimal. Option C multiplies by 10 instead of dividing by 1000.
Option D shifts the decimal two places incorrectly. Volume conversions are essential for
blood transfusion and fluid replacement calculations.
Q8: Which substance is classified as a heterogeneous mixture?
A. Saline solution (0.9% NaCl)
B. Blood with cells and plasma [CORRECT]
C. Distilled water
D. Oxygen gas
Correct Answer: B
Rationale: Blood is a heterogeneous mixture because its components (cells, plasma,
proteins) are not uniformly distributed at the microscopic level. Saline is a
homogeneous solution. Distilled water and oxygen gas are pure substances.
Understanding mixture types helps in separating blood components for transfusion and
analysis.
Q9: The specific gravity of urine is measured as 1.020. If the density of water is 1.000
g/mL at 4°C, what is the density of this urine sample?
A. 0.980 g/mL
, B. 1.000 g/mL
C. 1.020 g/mL [CORRECT]
D. 2.020 g/mL
Correct Answer: C
Rationale: Specific gravity = density of substance/density of water, so density = 1.020 ×
1.000 g/mL = 1.020 g/mL. Option A subtracts instead of multiplying. Option B assumes
the sample equals water density. Option D adds the values. Specific gravity is a key
diagnostic indicator of kidney function and hydration status.
Q10: Convert 37.0°C to Kelvin.
A. 273 K
B. 310 K [CORRECT]
C. 236 K
D. 346 K
Correct Answer: B
Rationale: K = °C + 273.15; 37.0 + 273.15 = 310.15 K, which rounds to 310 K. Option A
uses 273 without adding the temperature. Option C subtracts instead of adding. Option
D incorrectly adds 273 to 73 instead of 37. Temperature conversions are critical for gas
law calculations and biological temperature monitoring.
SECTION 2: Atomic Structure & Periodic Table (Q11–Q20)
Q11: Which subatomic particle carries a negative charge and has a mass approximately
1/1836 that of a proton?
A. Neutron
B. Proton
C. Electron [CORRECT]
D. Positron
Correct Answer: C
Rationale: Electrons carry a -1 charge and have a negligible mass (~0.00055 amu)
compared to protons. Neutrons are neutral, protons are positively charged, and
positrons are antimatter particles not found in standard atomic structure.
Highly Rated | Graded A+ | Pass Guaranteed - A+ Graded
SECTION 1: Matter, Measurement & Unit Conversions (Q1–Q10)
Q1: A nurse needs to administer 0.250 g of a medication, but the syringe is marked in
milligrams. How many milligrams should the nurse draw up?
A. 2.50 mg
B. 25.0 mg
C. 250 mg [CORRECT]
D. 2500 mg
Correct Answer: C
Rationale: Since 1 g = 1000 mg, 0.250 g × 1000 = 250 mg. Option A incorrectly shifts the
decimal one place, B shifts it two places, and D multiplies by 10,000. Accurate metric
conversions are essential in clinical dosing to prevent medication errors.
Q2: Express the number 0.004560 in scientific notation with the correct number of
significant figures.
A. 4.56 × 10⁻³
B. 4.560 × 10⁻³ [CORRECT]
C. 4.5600 × 10⁻³
D. 4560 × 10⁻⁶
Correct Answer: B
Rationale: The leading zeros are not significant, but the trailing zero after the decimal is
significant, giving four significant figures. Option A drops the significant trailing zero.
Option C adds an extra insignificant zero. Option D is not proper scientific notation and
obscures significant figures.
Q3: The density of a saline solution is 1.025 g/mL. What is the mass of 500.0 mL of this
solution?
A. 488.0 g
,B. 512.5 g [CORRECT]
C. 487.8 g
D. 2.050 g
Correct Answer: B
Rationale: Using density = mass/volume, mass = 1.025 g/mL × 500.0 mL = 512.5 g.
Option A incorrectly divides density by volume. Option C inverts the density value.
Option D doubles the density without multiplying by volume. Density calculations are
critical for preparing IV solutions.
Q4: Which of the following represents a physical change rather than a chemical change?
A. Rusting of iron
B. Digestion of food
C. Dissolving sugar in water [CORRECT]
D. Burning of gasoline
Correct Answer: C
Rationale: Dissolving sugar is a physical change because the sugar molecules remain
intact and can be recovered by evaporation. Rusting, digestion, and combustion all
involve chemical reactions that alter molecular composition. Distinguishing physical
and chemical changes is foundational for understanding drug stability and metabolism.
Q5: A patient weighs 154 lbs. What is their mass in kilograms? (1 lb = 0.4536 kg)
A. 34.0 kg
B. 68.0 kg
C. 70.0 kg [CORRECT]
D. 339 kg
Correct Answer: C
Rationale: 154 lbs × 0.4536 kg/lb = 69.85 kg, which rounds to 70.0 kg. Option A uses an
incorrect conversion factor. Option B uses approximately 0.44 kg/lb. Option D divides by
0.4536 instead of multiplying. Weight-to-mass conversions are routine in calculating
drug dosages per kg body weight.
Q6: How many significant figures are in the measurement 0.003020 m?
A. 3
B. 4 [CORRECT]
C. 6
,D. 7
Correct Answer: B
Rationale: Leading zeros are not significant; the digits 3, 0, 2, and the trailing zero after
the decimal are significant, giving four significant figures. Option A misses the trailing
zero. Option C counts leading zeros. Option D counts all zeros. Significant figures
ensure precision in laboratory measurements and clinical diagnostics.
Q7: A clinical laboratory measures a blood volume as 4.50 × 10³ mL. What is this
volume in liters?
A. 0.450 L
B. 4.50 L [CORRECT]
C. 45.0 L
D. 450 L
Correct Answer: B
Rationale: 4.50 × 10³ mL = 4500 mL. Dividing by 1000 mL/L gives 4.50 L. Option A
incorrectly shifts the decimal. Option C multiplies by 10 instead of dividing by 1000.
Option D shifts the decimal two places incorrectly. Volume conversions are essential for
blood transfusion and fluid replacement calculations.
Q8: Which substance is classified as a heterogeneous mixture?
A. Saline solution (0.9% NaCl)
B. Blood with cells and plasma [CORRECT]
C. Distilled water
D. Oxygen gas
Correct Answer: B
Rationale: Blood is a heterogeneous mixture because its components (cells, plasma,
proteins) are not uniformly distributed at the microscopic level. Saline is a
homogeneous solution. Distilled water and oxygen gas are pure substances.
Understanding mixture types helps in separating blood components for transfusion and
analysis.
Q9: The specific gravity of urine is measured as 1.020. If the density of water is 1.000
g/mL at 4°C, what is the density of this urine sample?
A. 0.980 g/mL
, B. 1.000 g/mL
C. 1.020 g/mL [CORRECT]
D. 2.020 g/mL
Correct Answer: C
Rationale: Specific gravity = density of substance/density of water, so density = 1.020 ×
1.000 g/mL = 1.020 g/mL. Option A subtracts instead of multiplying. Option B assumes
the sample equals water density. Option D adds the values. Specific gravity is a key
diagnostic indicator of kidney function and hydration status.
Q10: Convert 37.0°C to Kelvin.
A. 273 K
B. 310 K [CORRECT]
C. 236 K
D. 346 K
Correct Answer: B
Rationale: K = °C + 273.15; 37.0 + 273.15 = 310.15 K, which rounds to 310 K. Option A
uses 273 without adding the temperature. Option C subtracts instead of adding. Option
D incorrectly adds 273 to 73 instead of 37. Temperature conversions are critical for gas
law calculations and biological temperature monitoring.
SECTION 2: Atomic Structure & Periodic Table (Q11–Q20)
Q11: Which subatomic particle carries a negative charge and has a mass approximately
1/1836 that of a proton?
A. Neutron
B. Proton
C. Electron [CORRECT]
D. Positron
Correct Answer: C
Rationale: Electrons carry a -1 charge and have a negligible mass (~0.00055 amu)
compared to protons. Neutrons are neutral, protons are positively charged, and
positrons are antimatter particles not found in standard atomic structure.
