General Lab Chemistry I - Final Exam (CHEM 103) 2026/2027 UPDATE
1. A student measures the mass of a sample three times and gets 5.02g, 5.01g,
and 5.03g. The actual mass is 7.50g. How would these measurements be
described?
A. High accuracy and high precision
B. Low accuracy and high precision
C. High accuracy and low precision
D. Low accuracy and low precision
Answer: B
Rationale: Precision refers to how close measurements are to each other, while accuracy
refers to how close they are to the true value.
2. How many significant figures are in the measurement 0.004050 L?
A. 3
B. 5
C. 4
D. 6
Answer: C
Rationale: Leading zeros are not significant, but trailing zeros after a decimal and
sandwiched zeros are. Thus, 4, 0, 5, and the last 0 are significant.
,3. An object has a mass of 15.0 g and a volume of 3.0 mL. What is its density?
A. 0.2 g/mL
B. 45.0 g/mL
C. 12.0 g/mL
D. 5.0 g/mL
Answer: D
Rationale: Density is calculated by mass divided by volume (15.0g / 3.0mL = 5.0 g/mL).
4. Which of the following is an example of a chemical change?
A. Melting ice
B. Dissolving sugar in water
C. Crushing a can
D. Iron rusting
Answer: D
Rationale: Rusting is a chemical reaction (oxidation) that forms a new substance, whereas
the others are physical changes.
5. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C
Rationale: Electrons are negatively charged, protons are positive, and neutrons have no
charge.
, 6. What is the atomic number of an atom with 15 protons, 16 neutrons, and 15
electrons?
A. 1
B. 16
C. 31
D. 15
Answer: D
Rationale: The atomic number is defined solely by the number of protons in the nucleus.
7. Isotopes of the same element have different numbers of:
A. Protons
B. Electrons
C. Neutrons
D. Bonds
Answer: C
Rationale: Isotopes are atoms of the same element (same protons) with different masses
due to different neutron counts.
8. Which group on the periodic table is known as the Halogens?
A. Group 1
B. Group 2
C. Group 17
D. Group 18
Answer: C
Rationale: Group 17 elements (F, Cl, Br, I, At) are the Halogens.
1. A student measures the mass of a sample three times and gets 5.02g, 5.01g,
and 5.03g. The actual mass is 7.50g. How would these measurements be
described?
A. High accuracy and high precision
B. Low accuracy and high precision
C. High accuracy and low precision
D. Low accuracy and low precision
Answer: B
Rationale: Precision refers to how close measurements are to each other, while accuracy
refers to how close they are to the true value.
2. How many significant figures are in the measurement 0.004050 L?
A. 3
B. 5
C. 4
D. 6
Answer: C
Rationale: Leading zeros are not significant, but trailing zeros after a decimal and
sandwiched zeros are. Thus, 4, 0, 5, and the last 0 are significant.
,3. An object has a mass of 15.0 g and a volume of 3.0 mL. What is its density?
A. 0.2 g/mL
B. 45.0 g/mL
C. 12.0 g/mL
D. 5.0 g/mL
Answer: D
Rationale: Density is calculated by mass divided by volume (15.0g / 3.0mL = 5.0 g/mL).
4. Which of the following is an example of a chemical change?
A. Melting ice
B. Dissolving sugar in water
C. Crushing a can
D. Iron rusting
Answer: D
Rationale: Rusting is a chemical reaction (oxidation) that forms a new substance, whereas
the others are physical changes.
5. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C
Rationale: Electrons are negatively charged, protons are positive, and neutrons have no
charge.
, 6. What is the atomic number of an atom with 15 protons, 16 neutrons, and 15
electrons?
A. 1
B. 16
C. 31
D. 15
Answer: D
Rationale: The atomic number is defined solely by the number of protons in the nucleus.
7. Isotopes of the same element have different numbers of:
A. Protons
B. Electrons
C. Neutrons
D. Bonds
Answer: C
Rationale: Isotopes are atoms of the same element (same protons) with different masses
due to different neutron counts.
8. Which group on the periodic table is known as the Halogens?
A. Group 1
B. Group 2
C. Group 17
D. Group 18
Answer: C
Rationale: Group 17 elements (F, Cl, Br, I, At) are the Halogens.
