Portage Learning CHEM 103 General Chemistry I
2026/2027 — Final Comprehensive Examination
Questions with Answers
1. Which of the following is a chemical property of matter?
• A. Density
• B. Melting point
• C. Flammability
• D. Solubility
Correct Answer: C
Rationale: A chemical property describes a substance's ability to undergo a
chemical change or reaction. Flammability is the ability to burn, which is a
chemical reaction. Density, melting point, and solubility are physical properties, as
they can be observed without changing the substance's chemical identity.
2. How many significant figures are in the measurement 0.004050 kg?
• A. 3
• B. 4
• C. 5
• D. 7
Correct Answer: B
Rationale: Significant figures include all non-zero digits, zeros between non-
zero digits, and trailing zeros after a decimal point. In 0.004050, the leading zeros
(0.00) are not significant. The non-zero digits (4 and 5) are significant. The zero
between 4 and 5 is significant. The trailing zero after 5 is significant. Therefore,
there are 4 significant figures.
,3. An atom of an element has an atomic number of 19 and a mass number of 39.
How many neutrons does it have?
• A. 19
• B. 20
• C. 39
• D. 58
Correct Answer: B
Rationale: The number of neutrons is calculated by subtracting the atomic
number (number of protons) from the mass number. Neutrons = Mass Number -
Atomic Number = 39 - 19 = 20.
4. Which of the following represents a transition metal?
• A. Sodium (Na)
• B. Calcium (Ca)
• C. Iron (Fe)
• D. Sulfur (S)
Correct Answer: C
Rationale: Transition metals are found in the d-block of the periodic table
(Groups 3-12). Iron (Fe) is in Group 8, making it a transition metal. Sodium and
calcium are in Groups 1 and 2 (main group metals), and sulfur is a nonmetal in
Group 16.
5. What is the correct formula for the ionic compound formed from aluminum
and oxygen?
• A. AlO
• B. Al₂O₃
• C. Al₃O₂
, • D. AlO₂
Correct Answer: B
Rationale: Aluminum forms a +3 ion (Al³⁺), and oxygen forms a -2 ion (O²⁻). To
form a neutral compound, the total positive charge must equal the total negative
charge. The least common multiple of 3 and 2 is 6. This requires two Al³⁺ ions
(total +6) and three O²⁻ ions (total -6). The resulting formula is Al₂O₃.
6. The molar mass of calcium phosphate, Ca₃(PO₄)₂, is:
• A. 215.21 g/mol
• B. 279.21 g/mol
• C. 310.18 g/mol
• D. 340.18 g/mol
Correct Answer: C
Rationale: Calculate the molar mass by summing the atomic masses of all
atoms in the formula: 3 Ca (40.08 g/mol) + 2 P (30.97 g/mol) + 8 O (16.00 g/mol) =
(3 × 40.08) + (2 × 30.97) + (8 × 16.00) = 120.24 + 61.94 + 128.00 = 310.18 g/mol.
7. Which of the following is a strong electrolyte when dissolved in water?
• A. CH₃OH (Methanol)
• B. C₆H₁₂O₆ (Glucose)
• C. NaCl (Sodium Chloride)
• D. H₂CO₃ (Carbonic Acid)
Correct Answer: C
Rationale: Strong electrolytes completely dissociate into ions in water. NaCl is
a soluble ionic compound that dissociates completely into Na⁺ and Cl⁻ ions.
Methanol and glucose are nonelectrolytes (molecular compounds that do not
form ions). Carbonic acid is a weak electrolyte (a weak acid that only partially
ionizes).
, 8. What is the oxidation state of manganese in the permanganate ion, MnO₄⁻?
• A. +2
• B. +4
• C. +7
• D. -1
Correct Answer: C
Rationale: The sum of oxidation states in a polyatomic ion equals the ion's
charge. Oxygen typically has an oxidation state of -2. Let x be the oxidation state
of Mn. So, x + 4(-2) = -1. x - 8 = -1, therefore x = +7.
9. According to the kinetic molecular theory, which statement is true for an ideal
gas?
• A. Gas particles have a significant volume.
• B. Gas particles attract and repel each other.
• C. The average kinetic energy of gas particles is proportional to the Kelvin
temperature.
• D. Collisions between gas particles are inelastic.
Correct Answer: C
Rationale: A key postulate of the kinetic molecular theory is that the average
kinetic energy of gas particles is directly proportional to the absolute temperature
(in Kelvin). The other options are false: gas particles have negligible volume, there
are no attractive or repulsive forces between them, and collisions are perfectly
elastic.
10. A 2.0 L sample of gas at 1.0 atm is compressed to a volume of 0.50 L at a
constant temperature. What is the new pressure?
• A. 0.25 atm
• B. 1.0 atm
2026/2027 — Final Comprehensive Examination
Questions with Answers
1. Which of the following is a chemical property of matter?
• A. Density
• B. Melting point
• C. Flammability
• D. Solubility
Correct Answer: C
Rationale: A chemical property describes a substance's ability to undergo a
chemical change or reaction. Flammability is the ability to burn, which is a
chemical reaction. Density, melting point, and solubility are physical properties, as
they can be observed without changing the substance's chemical identity.
2. How many significant figures are in the measurement 0.004050 kg?
• A. 3
• B. 4
• C. 5
• D. 7
Correct Answer: B
Rationale: Significant figures include all non-zero digits, zeros between non-
zero digits, and trailing zeros after a decimal point. In 0.004050, the leading zeros
(0.00) are not significant. The non-zero digits (4 and 5) are significant. The zero
between 4 and 5 is significant. The trailing zero after 5 is significant. Therefore,
there are 4 significant figures.
,3. An atom of an element has an atomic number of 19 and a mass number of 39.
How many neutrons does it have?
• A. 19
• B. 20
• C. 39
• D. 58
Correct Answer: B
Rationale: The number of neutrons is calculated by subtracting the atomic
number (number of protons) from the mass number. Neutrons = Mass Number -
Atomic Number = 39 - 19 = 20.
4. Which of the following represents a transition metal?
• A. Sodium (Na)
• B. Calcium (Ca)
• C. Iron (Fe)
• D. Sulfur (S)
Correct Answer: C
Rationale: Transition metals are found in the d-block of the periodic table
(Groups 3-12). Iron (Fe) is in Group 8, making it a transition metal. Sodium and
calcium are in Groups 1 and 2 (main group metals), and sulfur is a nonmetal in
Group 16.
5. What is the correct formula for the ionic compound formed from aluminum
and oxygen?
• A. AlO
• B. Al₂O₃
• C. Al₃O₂
, • D. AlO₂
Correct Answer: B
Rationale: Aluminum forms a +3 ion (Al³⁺), and oxygen forms a -2 ion (O²⁻). To
form a neutral compound, the total positive charge must equal the total negative
charge. The least common multiple of 3 and 2 is 6. This requires two Al³⁺ ions
(total +6) and three O²⁻ ions (total -6). The resulting formula is Al₂O₃.
6. The molar mass of calcium phosphate, Ca₃(PO₄)₂, is:
• A. 215.21 g/mol
• B. 279.21 g/mol
• C. 310.18 g/mol
• D. 340.18 g/mol
Correct Answer: C
Rationale: Calculate the molar mass by summing the atomic masses of all
atoms in the formula: 3 Ca (40.08 g/mol) + 2 P (30.97 g/mol) + 8 O (16.00 g/mol) =
(3 × 40.08) + (2 × 30.97) + (8 × 16.00) = 120.24 + 61.94 + 128.00 = 310.18 g/mol.
7. Which of the following is a strong electrolyte when dissolved in water?
• A. CH₃OH (Methanol)
• B. C₆H₁₂O₆ (Glucose)
• C. NaCl (Sodium Chloride)
• D. H₂CO₃ (Carbonic Acid)
Correct Answer: C
Rationale: Strong electrolytes completely dissociate into ions in water. NaCl is
a soluble ionic compound that dissociates completely into Na⁺ and Cl⁻ ions.
Methanol and glucose are nonelectrolytes (molecular compounds that do not
form ions). Carbonic acid is a weak electrolyte (a weak acid that only partially
ionizes).
, 8. What is the oxidation state of manganese in the permanganate ion, MnO₄⁻?
• A. +2
• B. +4
• C. +7
• D. -1
Correct Answer: C
Rationale: The sum of oxidation states in a polyatomic ion equals the ion's
charge. Oxygen typically has an oxidation state of -2. Let x be the oxidation state
of Mn. So, x + 4(-2) = -1. x - 8 = -1, therefore x = +7.
9. According to the kinetic molecular theory, which statement is true for an ideal
gas?
• A. Gas particles have a significant volume.
• B. Gas particles attract and repel each other.
• C. The average kinetic energy of gas particles is proportional to the Kelvin
temperature.
• D. Collisions between gas particles are inelastic.
Correct Answer: C
Rationale: A key postulate of the kinetic molecular theory is that the average
kinetic energy of gas particles is directly proportional to the absolute temperature
(in Kelvin). The other options are false: gas particles have negligible volume, there
are no attractive or repulsive forces between them, and collisions are perfectly
elastic.
10. A 2.0 L sample of gas at 1.0 atm is compressed to a volume of 0.50 L at a
constant temperature. What is the new pressure?
• A. 0.25 atm
• B. 1.0 atm
