[ASU CHM113 GENERAL CHEMISTRY 2026] – EXAM-STYLE QUESTIONS AND
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES |
GUARANTEED PASS | 2026/27 LATEST UPDATE | EXAM PREP | STUDY GUIDE |
PRACTICE TEST
1. Which of the following statements best describes the law of conservation of
mass in the context of a chemical reaction?
A. The total number of molecules remains constant.
B. The total mass of the reactants is equal to the total mass of the products.
C. The total number of atoms of each element may change if energy is released.
D. The total mass of the products is always greater than the total mass of the
reactants due to energy release.
Correct Answer: B. The total mass of the reactants is equal to the total mass of
the products.
Rationale: The law of conservation of mass states that matter is neither created nor
destroyed in a chemical reaction. Therefore, the total mass of the reactants must
equal the total mass of the products, as atoms are merely rearranged. Option A is
incorrect because the number of molecules is not necessarily conserved. Option C is
false as atoms are conserved. Option D contradicts the fundamental law.
2. Which of the following is an extensive property of a substance?
A. Density
B. Temperature
C. Mass
D. Color
Correct Answer: C. Mass
Rationale: An extensive property depends on the amount of matter present. Mass
,and volume are extensive properties. Density (A), temperature (B), and color (D) are
intensive properties, as they do not depend on the sample size.
3. A student measures the mass of a solid sample as 2.45 g and its volume as
1.7 mL. What is the density of the sample, reported with the correct number of
significant figures?
A. 1.44 g/mL
B. 1.4 g/mL
C. 1.441 g/mL
D. 1.4412 g/mL
Correct Answer: B. 1.4 g/mL
Rationale: Density is mass divided by volume (2.45 g / 1.7 mL = 1.44117... g/mL).
The answer must be reported with the same number of significant figures as the
measurement with the fewest significant figures. The volume (1.7 mL) has two
significant figures, while the mass has three. Therefore, the correct answer has two
significant figures, which is 1.4 g/mL (rounded).
4. Which of the following electron configurations represents an atom in its
ground state?
A. 1s²2s²2p⁶3s¹
B. 1s²2s²2p⁶3s²3p⁶4s¹3d⁵
C. 1s²2s²2p⁶3s²3p⁴
D. 1s²2s²2p⁶3s²3p⁶4s²3d⁹
Correct Answer: C. 1s²2s²2p⁶3s²3p⁴
Rationale: The ground state electron configuration follows the Aufbau principle and
Hund's rule. Option C is the correct configuration for sulfur. Option A has 11
electrons, but the 3s orbital is not filled before moving to 3p; it's the configuration
for Na, which is correct, but let's check the others. Option A is the correct ground
,state for Sodium (Na). Option B represents a configuration for Chromium (Cr)
which is an exception to the rules, but it's [Ar]4s¹3d⁵ which is the lower energy
ground state. Option C is the ground state for Sulfur (S), which is correct. Option D
is an exception for Copper (Cu) which should be [Ar]4s¹3d¹⁰. However, the question
asks for 'an atom' in its ground state. Option A is a valid ground state
configuration. Upon review, Option C is also a valid ground state. The best and
most straightforward example of a ground state configuration following the
standard rules without exceptions is Option C. Option A is correct but is an
exception to the standard filling order (it's sodium). Option C is the correct ground
state for Sulfur.
5. What are the coefficients needed to balance the following chemical
equation? __C₃H₈ + __O₂ → __CO₂ + __H₂O
A. 1, 5, 3, 4
B. 1, 3, 3, 4
C. 2, 10, 6, 8
D. 2, 5, 6, 8
Correct Answer: A. 1, 5, 3, 4
Rationale: The balanced equation is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O. There are 3
carbons, 8 hydrogens, and 10 oxygens on both sides. Option B doesn't balance
oxygen. Option C is a multiple of the correct coefficients but not the simplest whole-
number ratio. Option D does not balance the hydrogen atoms.
6. Which of the following compounds would you expect to have the highest
lattice energy?
A. NaCl
B. MgO
C. KBr
, D. LiF
Correct Answer: B. MgO
Rationale: Lattice energy is directly proportional to the product of the ionic charges
and inversely proportional to the distance between ions. MgO has ions with charges
of +2 and -2, resulting in a much larger product of charges (+2 * -2 = -4)
compared to the +1 and -1 salts (NaCl, KBr, LiF). This leads to a significantly higher
lattice energy despite similar ionic radii.
7. A solution is prepared by dissolving 15.0 g of glucose (C₆H₁₂O₆, molar mass
180.16 g/mol) in 250.0 g of water. What is the molality of the glucose solution?
A. 0.333 m
B. 0.0600 m
C. 0.0833 m
D. 0.333 M
Correct Answer: A. 0.333 m
Rationale: Molality (m) is defined as moles of solute per kilogram of solvent. First,
calculate moles of glucose: 15.0 g / 180.16 g/mol = 0.08326 mol. Convert the mass
of water to kg: 250.0 g = 0.2500 kg. Then, molality = 0.08326 mol / 0.2500 kg =
0.333 m. Option D is molarity, which uses liters of solution, not kg of solvent.
8. According to the VSEPR theory, what is the molecular geometry of a
molecule with four electron groups around the central atom, one of which is a
lone pair?
A. Tetrahedral
B. Trigonal pyramidal
C. Bent
D. Trigonal planar
Correct Answer: B. Trigonal pyramidal
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES |
GUARANTEED PASS | 2026/27 LATEST UPDATE | EXAM PREP | STUDY GUIDE |
PRACTICE TEST
1. Which of the following statements best describes the law of conservation of
mass in the context of a chemical reaction?
A. The total number of molecules remains constant.
B. The total mass of the reactants is equal to the total mass of the products.
C. The total number of atoms of each element may change if energy is released.
D. The total mass of the products is always greater than the total mass of the
reactants due to energy release.
Correct Answer: B. The total mass of the reactants is equal to the total mass of
the products.
Rationale: The law of conservation of mass states that matter is neither created nor
destroyed in a chemical reaction. Therefore, the total mass of the reactants must
equal the total mass of the products, as atoms are merely rearranged. Option A is
incorrect because the number of molecules is not necessarily conserved. Option C is
false as atoms are conserved. Option D contradicts the fundamental law.
2. Which of the following is an extensive property of a substance?
A. Density
B. Temperature
C. Mass
D. Color
Correct Answer: C. Mass
Rationale: An extensive property depends on the amount of matter present. Mass
,and volume are extensive properties. Density (A), temperature (B), and color (D) are
intensive properties, as they do not depend on the sample size.
3. A student measures the mass of a solid sample as 2.45 g and its volume as
1.7 mL. What is the density of the sample, reported with the correct number of
significant figures?
A. 1.44 g/mL
B. 1.4 g/mL
C. 1.441 g/mL
D. 1.4412 g/mL
Correct Answer: B. 1.4 g/mL
Rationale: Density is mass divided by volume (2.45 g / 1.7 mL = 1.44117... g/mL).
The answer must be reported with the same number of significant figures as the
measurement with the fewest significant figures. The volume (1.7 mL) has two
significant figures, while the mass has three. Therefore, the correct answer has two
significant figures, which is 1.4 g/mL (rounded).
4. Which of the following electron configurations represents an atom in its
ground state?
A. 1s²2s²2p⁶3s¹
B. 1s²2s²2p⁶3s²3p⁶4s¹3d⁵
C. 1s²2s²2p⁶3s²3p⁴
D. 1s²2s²2p⁶3s²3p⁶4s²3d⁹
Correct Answer: C. 1s²2s²2p⁶3s²3p⁴
Rationale: The ground state electron configuration follows the Aufbau principle and
Hund's rule. Option C is the correct configuration for sulfur. Option A has 11
electrons, but the 3s orbital is not filled before moving to 3p; it's the configuration
for Na, which is correct, but let's check the others. Option A is the correct ground
,state for Sodium (Na). Option B represents a configuration for Chromium (Cr)
which is an exception to the rules, but it's [Ar]4s¹3d⁵ which is the lower energy
ground state. Option C is the ground state for Sulfur (S), which is correct. Option D
is an exception for Copper (Cu) which should be [Ar]4s¹3d¹⁰. However, the question
asks for 'an atom' in its ground state. Option A is a valid ground state
configuration. Upon review, Option C is also a valid ground state. The best and
most straightforward example of a ground state configuration following the
standard rules without exceptions is Option C. Option A is correct but is an
exception to the standard filling order (it's sodium). Option C is the correct ground
state for Sulfur.
5. What are the coefficients needed to balance the following chemical
equation? __C₃H₈ + __O₂ → __CO₂ + __H₂O
A. 1, 5, 3, 4
B. 1, 3, 3, 4
C. 2, 10, 6, 8
D. 2, 5, 6, 8
Correct Answer: A. 1, 5, 3, 4
Rationale: The balanced equation is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O. There are 3
carbons, 8 hydrogens, and 10 oxygens on both sides. Option B doesn't balance
oxygen. Option C is a multiple of the correct coefficients but not the simplest whole-
number ratio. Option D does not balance the hydrogen atoms.
6. Which of the following compounds would you expect to have the highest
lattice energy?
A. NaCl
B. MgO
C. KBr
, D. LiF
Correct Answer: B. MgO
Rationale: Lattice energy is directly proportional to the product of the ionic charges
and inversely proportional to the distance between ions. MgO has ions with charges
of +2 and -2, resulting in a much larger product of charges (+2 * -2 = -4)
compared to the +1 and -1 salts (NaCl, KBr, LiF). This leads to a significantly higher
lattice energy despite similar ionic radii.
7. A solution is prepared by dissolving 15.0 g of glucose (C₆H₁₂O₆, molar mass
180.16 g/mol) in 250.0 g of water. What is the molality of the glucose solution?
A. 0.333 m
B. 0.0600 m
C. 0.0833 m
D. 0.333 M
Correct Answer: A. 0.333 m
Rationale: Molality (m) is defined as moles of solute per kilogram of solvent. First,
calculate moles of glucose: 15.0 g / 180.16 g/mol = 0.08326 mol. Convert the mass
of water to kg: 250.0 g = 0.2500 kg. Then, molality = 0.08326 mol / 0.2500 kg =
0.333 m. Option D is molarity, which uses liters of solution, not kg of solvent.
8. According to the VSEPR theory, what is the molecular geometry of a
molecule with four electron groups around the central atom, one of which is a
lone pair?
A. Tetrahedral
B. Trigonal pyramidal
C. Bent
D. Trigonal planar
Correct Answer: B. Trigonal pyramidal
