UNE GENERAL CHEMISTRY 2 MIDTERM EXAM 2026/2027 |
COMPLETE QUESTIONS AND ANSWERS (VERIFIED ANSWERS) |
EXAM PREP | COMPREHENSIVE EXAM GUIDE 2026&2027
1. A 0.100 M solution of a weak acid HA has a pH of 2.90. Which statement best
describes the acid?
A. HA is completely dissociated in water.
B. HA is a strong base.
C. HA is partially dissociated in water.
D. HA cannot react with water.
Answer: C
A weak acid establishes an equilibrium with water rather than dissociating completely. A pH
of 2.90 for a 0.100 M solution is consistent with partial ionization.
2. A student titrates 25.00 mL of 0.200 M HCl with 0.100 M NaOH. What volume of
NaOH is required to reach the equivalence point?
A. 25.0 mL
B. 50.0 mL
C. 75.0 mL
D. 100.0 mL
Answer: B
HCl and NaOH react in a 1:1 ratio. The initial HCl amount is 0.00500 mol, requiring 0.00500
mol NaOH. At 0.100 M, this requires 0.0500 L, or 50.0 mL.
3. Which change would increase the rate of a reaction between a solid metal and an
aqueous acid without changing the reaction stoichiometry?
A. Decreasing the temperature
B. Using larger pieces of the metal
C. Decreasing the acid concentration
D. Increasing the surface area of the metal
Answer: D
Increasing surface area exposes more reactive particles to the acid, increasing the frequency
of effective collisions and therefore increasing reaction rate.
4. For the equilibrium N2(g) + 3H2(g) ⇌ 2NH3(g), what happens when additional H2
is introduced at constant temperature?
A. The equilibrium shifts toward NH3.
B. The equilibrium constant decreases.
, C. The equilibrium shifts toward N2 and H2.
D. The reaction stops temporarily.
Answer: A
Adding a reactant causes the system to shift toward products to consume part of the added
H2, according to Le Châtelier's principle.
5. Which expression correctly represents the equilibrium constant Kc for CaCO3(s) ⇌
CaO(s) + CO2(g)?
A. [CaO][CO2]/[CaCO3]
B. [CaCO3]/[CaO][CO2]
C. [CO2]
D. [CaO][CaCO3][CO2]
Answer: C
Pure solids are omitted from equilibrium expressions because their activities are effectively
constant. Therefore, Kc = [CO2].
6. A reaction has a large positive ΔG under specified conditions. What does this
indicate?
A. The reaction is spontaneous in the forward direction.
B. The reaction is nonspontaneous in the forward direction under those conditions.
C. The reaction must be fast.
D. The reaction must be exothermic.
Answer: B
A positive Gibbs free-energy change means the forward reaction is thermodynamically
nonspontaneous under the stated conditions. Reaction rate and heat flow are separate
considerations.
7. Which species is the strongest oxidizing agent among the following?
A. A species with E°red = +1.50 V
B. A species with E°red = +0.20 V
C. A species with E°red = −0.50 V
D. A species with E°red = −1.20 V
Answer: A
A more positive standard reduction potential indicates a greater tendency to gain electrons.
Therefore, the species with +1.50 V is the strongest oxidizing agent.
8. In a galvanic cell operating spontaneously under standard conditions, where does
oxidation occur?
, A. At the cathode
B. At the salt bridge
C. At the anode
D. In the external wire
Answer: C
Oxidation always occurs at the anode, while reduction occurs at the cathode. In a galvanic
cell, oxidation at the anode supplies electrons to the external circuit.
9. Which quantum number identifies the principal energy level occupied by an
electron?
A. n
B. l
C. ml
D. ms
Answer: A
The principal quantum number n specifies the primary energy level and is related to the
average distance of an electron from the nucleus.
10. Why does the first ionization energy generally increase from left to right across a
period?
A. Atomic mass decreases.
B. Effective nuclear charge generally increases.
C. The number of occupied shells increases.
D. Electrons become farther from the nucleus.
Answer: B
Across a period, nuclear charge increases while electrons are added to the same principal
energy level. The resulting increase in effective nuclear charge makes electron removal more
difficult.
11. Which molecular geometry is predicted for BF3 using VSEPR theory?
A. Bent
B. Tetrahedral
C. Trigonal pyramidal
D. Trigonal planar
Answer: D
Boron in BF3 has three bonding regions and no lone pairs on the central atom, producing a
trigonal planar molecular geometry.
, 12. What is the hybridization of the central carbon atom in CO2?
A. sp3
B. sp2
C. sp
D. dsp2
Answer: C
The carbon atom has two electron domains associated with the two double bonds, giving a
linear arrangement and sp hybridization.
13. Which intermolecular force is primarily responsible for the unusually high boiling
point of water?
A. London dispersion forces
B. Hydrogen bonding
C. Ion-dipole interactions
D. Metallic bonding
Answer: B
Water molecules form extensive hydrogen-bonding networks because hydrogen is directly
bonded to highly electronegative oxygen.
14. A sample of gas occupies 2.00 L at 300 K. If pressure remains constant and
temperature increases to 450 K, what volume will the gas occupy?
A. 1.33 L
B. 2.00 L
C. 2.50 L
D. 3.00 L
Answer: D
At constant pressure, Charles's law gives V1/T1 = V2/T2. Thus V2 = 2.00 × 450/300 = 3.00 L.
15. Which gas would diffuse most rapidly at the same temperature and pressure?
A. H2
B. O2
C. N2
D. CO2
Answer: A
According to Graham's law, diffusion rate is inversely proportional to the square root of molar
mass. H2 has the lowest molar mass among these gases.
COMPLETE QUESTIONS AND ANSWERS (VERIFIED ANSWERS) |
EXAM PREP | COMPREHENSIVE EXAM GUIDE 2026&2027
1. A 0.100 M solution of a weak acid HA has a pH of 2.90. Which statement best
describes the acid?
A. HA is completely dissociated in water.
B. HA is a strong base.
C. HA is partially dissociated in water.
D. HA cannot react with water.
Answer: C
A weak acid establishes an equilibrium with water rather than dissociating completely. A pH
of 2.90 for a 0.100 M solution is consistent with partial ionization.
2. A student titrates 25.00 mL of 0.200 M HCl with 0.100 M NaOH. What volume of
NaOH is required to reach the equivalence point?
A. 25.0 mL
B. 50.0 mL
C. 75.0 mL
D. 100.0 mL
Answer: B
HCl and NaOH react in a 1:1 ratio. The initial HCl amount is 0.00500 mol, requiring 0.00500
mol NaOH. At 0.100 M, this requires 0.0500 L, or 50.0 mL.
3. Which change would increase the rate of a reaction between a solid metal and an
aqueous acid without changing the reaction stoichiometry?
A. Decreasing the temperature
B. Using larger pieces of the metal
C. Decreasing the acid concentration
D. Increasing the surface area of the metal
Answer: D
Increasing surface area exposes more reactive particles to the acid, increasing the frequency
of effective collisions and therefore increasing reaction rate.
4. For the equilibrium N2(g) + 3H2(g) ⇌ 2NH3(g), what happens when additional H2
is introduced at constant temperature?
A. The equilibrium shifts toward NH3.
B. The equilibrium constant decreases.
, C. The equilibrium shifts toward N2 and H2.
D. The reaction stops temporarily.
Answer: A
Adding a reactant causes the system to shift toward products to consume part of the added
H2, according to Le Châtelier's principle.
5. Which expression correctly represents the equilibrium constant Kc for CaCO3(s) ⇌
CaO(s) + CO2(g)?
A. [CaO][CO2]/[CaCO3]
B. [CaCO3]/[CaO][CO2]
C. [CO2]
D. [CaO][CaCO3][CO2]
Answer: C
Pure solids are omitted from equilibrium expressions because their activities are effectively
constant. Therefore, Kc = [CO2].
6. A reaction has a large positive ΔG under specified conditions. What does this
indicate?
A. The reaction is spontaneous in the forward direction.
B. The reaction is nonspontaneous in the forward direction under those conditions.
C. The reaction must be fast.
D. The reaction must be exothermic.
Answer: B
A positive Gibbs free-energy change means the forward reaction is thermodynamically
nonspontaneous under the stated conditions. Reaction rate and heat flow are separate
considerations.
7. Which species is the strongest oxidizing agent among the following?
A. A species with E°red = +1.50 V
B. A species with E°red = +0.20 V
C. A species with E°red = −0.50 V
D. A species with E°red = −1.20 V
Answer: A
A more positive standard reduction potential indicates a greater tendency to gain electrons.
Therefore, the species with +1.50 V is the strongest oxidizing agent.
8. In a galvanic cell operating spontaneously under standard conditions, where does
oxidation occur?
, A. At the cathode
B. At the salt bridge
C. At the anode
D. In the external wire
Answer: C
Oxidation always occurs at the anode, while reduction occurs at the cathode. In a galvanic
cell, oxidation at the anode supplies electrons to the external circuit.
9. Which quantum number identifies the principal energy level occupied by an
electron?
A. n
B. l
C. ml
D. ms
Answer: A
The principal quantum number n specifies the primary energy level and is related to the
average distance of an electron from the nucleus.
10. Why does the first ionization energy generally increase from left to right across a
period?
A. Atomic mass decreases.
B. Effective nuclear charge generally increases.
C. The number of occupied shells increases.
D. Electrons become farther from the nucleus.
Answer: B
Across a period, nuclear charge increases while electrons are added to the same principal
energy level. The resulting increase in effective nuclear charge makes electron removal more
difficult.
11. Which molecular geometry is predicted for BF3 using VSEPR theory?
A. Bent
B. Tetrahedral
C. Trigonal pyramidal
D. Trigonal planar
Answer: D
Boron in BF3 has three bonding regions and no lone pairs on the central atom, producing a
trigonal planar molecular geometry.
, 12. What is the hybridization of the central carbon atom in CO2?
A. sp3
B. sp2
C. sp
D. dsp2
Answer: C
The carbon atom has two electron domains associated with the two double bonds, giving a
linear arrangement and sp hybridization.
13. Which intermolecular force is primarily responsible for the unusually high boiling
point of water?
A. London dispersion forces
B. Hydrogen bonding
C. Ion-dipole interactions
D. Metallic bonding
Answer: B
Water molecules form extensive hydrogen-bonding networks because hydrogen is directly
bonded to highly electronegative oxygen.
14. A sample of gas occupies 2.00 L at 300 K. If pressure remains constant and
temperature increases to 450 K, what volume will the gas occupy?
A. 1.33 L
B. 2.00 L
C. 2.50 L
D. 3.00 L
Answer: D
At constant pressure, Charles's law gives V1/T1 = V2/T2. Thus V2 = 2.00 × 450/300 = 3.00 L.
15. Which gas would diffuse most rapidly at the same temperature and pressure?
A. H2
B. O2
C. N2
D. CO2
Answer: A
According to Graham's law, diffusion rate is inversely proportional to the square root of molar
mass. H2 has the lowest molar mass among these gases.
