CHEM 103 General Chemistry Midterm Exam
Newest 2025 – 2026 Questions From Actual
Exams Complete Questions And Correct Detailed
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Content Covered (Most Tested Topics):
Atomic structure, periodic trends, chemical bonding, molecular
geometry, stoichiometry, chemical equations, gases,
thermochemistry, solutions, and basic equilibrium concepts
1. Which subatomic particle has a positive charge?
A. Electron
B. Neutron
C. Proton
D. Photon
Answer: Proton
Protons carry a +1 charge and are located in the nucleus of an atom.
2. What is the atomic number of an element equal to?
A. Number of neutrons
B. Number of protons
C. Number of electrons and neutrons
D. Mass number
Answer: Number of protons
The atomic number uniquely identifies an element and equals the number of protons.
3. Which orbital holds a maximum of 2 electrons?
A. s orbital
B. p orbital
C. d orbital
D. f orbital
Answer: s orbital
An s orbital can hold a maximum of 2 electrons according to quantum rules.
4. Which principle states that no two electrons can have the same set of quantum numbers?
A. Aufbau principle
B. Hund’s rule
C. Pauli exclusion principle
D. Heisenberg uncertainty principle
Answer: Pauli exclusion principle
It ensures each electron in an atom has a unique quantum state.
5. Which element has the highest electronegativity?
A. Oxygen
, B. Fluorine
C. Chlorine
D. Nitrogen
Answer: Fluorine
Fluorine is the most electronegative element on the periodic table.
6. Atomic radius generally decreases across a period because:
A. Increased shielding
B. Increased nuclear charge
C. Decreased protons
D. Increased neutrons
Answer: Increased nuclear charge
Greater nuclear charge pulls electrons closer to the nucleus.
7. Which bond involves equal sharing of electrons?
A. Ionic
B. Polar covalent
C. Nonpolar covalent
D. Metallic
Answer: Nonpolar covalent
Electrons are shared equally between atoms of similar electronegativity.
8. What is the shape of a molecule with 2 bonding pairs and no lone pairs?
A. Bent
B. Linear
C. Trigonal planar
D. Tetrahedral
Answer: Linear
Two electron domains arrange themselves 180° apart.
9. What is the molar mass of H₂O?
A. 16 g/mol
B. 17 g/mol
C. 18 g/mol
D. 19 g/mol
Answer: 18 g/mol
2 hydrogens (1 each) + 1 oxygen (16) = 18 g/mol.
10. Which law states mass is conserved in a chemical reaction?
A. Boyle’s law
B. Charles’s law
C. Law of conservation of mass
D. Avogadro’s law
Answer: Law of conservation of mass
Mass is neither created nor destroyed in a chemical reaction.
11. Balance: H₂ + O₂ → H₂O. What is coefficient of H₂?
A. 1
B. 2
C. 3
D. 4
, Answer: 2
Balanced equation: 2H₂ + O₂ → 2H₂O.
12. What is 1 mole equal to?
A. 6.02 × 10²²
B. 6.02 × 10²³
C. 6.02 × 10²⁴
D. 6.02 × 10²⁵
Answer: 6.02 × 10²³
Avogadro’s number defines one mole.
13. Which is the limiting reagent?
A. Excess reactant
B. Reactant that runs out first
C. Catalyst
D. Solvent
Answer: Reactant that runs out first
It determines the maximum product formed.
14. Ideal gas law is expressed as:
A. PV = nRT
B. P = nRT
C. V = nRT
D. PV = RT
Answer: PV = nRT
Relates pressure, volume, moles, and temperature.
15. Increasing temperature at constant volume increases:
A. Volume
B. Pressure
C. Moles
D. Mass
Answer: Pressure
Higher temperature increases kinetic energy and pressure.
16. Which gas law relates pressure and volume inversely?
A. Charles’s law
B. Boyle’s law
C. Avogadro’s law
D. Dalton’s law
Answer: Boyle’s law
Pressure and volume are inversely proportional.
17. Heat absorbed by a system is:
A. Negative
B. Positive
C. Zero
D. Constant
Answer: Positive
Endothermic processes absorb heat.
18. Which process releases heat?
A. Endothermic
Newest 2025 – 2026 Questions From Actual
Exams Complete Questions And Correct Detailed
Answers (Verified Answers) |Already Graded
A+||Brand New!!
Content Covered (Most Tested Topics):
Atomic structure, periodic trends, chemical bonding, molecular
geometry, stoichiometry, chemical equations, gases,
thermochemistry, solutions, and basic equilibrium concepts
1. Which subatomic particle has a positive charge?
A. Electron
B. Neutron
C. Proton
D. Photon
Answer: Proton
Protons carry a +1 charge and are located in the nucleus of an atom.
2. What is the atomic number of an element equal to?
A. Number of neutrons
B. Number of protons
C. Number of electrons and neutrons
D. Mass number
Answer: Number of protons
The atomic number uniquely identifies an element and equals the number of protons.
3. Which orbital holds a maximum of 2 electrons?
A. s orbital
B. p orbital
C. d orbital
D. f orbital
Answer: s orbital
An s orbital can hold a maximum of 2 electrons according to quantum rules.
4. Which principle states that no two electrons can have the same set of quantum numbers?
A. Aufbau principle
B. Hund’s rule
C. Pauli exclusion principle
D. Heisenberg uncertainty principle
Answer: Pauli exclusion principle
It ensures each electron in an atom has a unique quantum state.
5. Which element has the highest electronegativity?
A. Oxygen
, B. Fluorine
C. Chlorine
D. Nitrogen
Answer: Fluorine
Fluorine is the most electronegative element on the periodic table.
6. Atomic radius generally decreases across a period because:
A. Increased shielding
B. Increased nuclear charge
C. Decreased protons
D. Increased neutrons
Answer: Increased nuclear charge
Greater nuclear charge pulls electrons closer to the nucleus.
7. Which bond involves equal sharing of electrons?
A. Ionic
B. Polar covalent
C. Nonpolar covalent
D. Metallic
Answer: Nonpolar covalent
Electrons are shared equally between atoms of similar electronegativity.
8. What is the shape of a molecule with 2 bonding pairs and no lone pairs?
A. Bent
B. Linear
C. Trigonal planar
D. Tetrahedral
Answer: Linear
Two electron domains arrange themselves 180° apart.
9. What is the molar mass of H₂O?
A. 16 g/mol
B. 17 g/mol
C. 18 g/mol
D. 19 g/mol
Answer: 18 g/mol
2 hydrogens (1 each) + 1 oxygen (16) = 18 g/mol.
10. Which law states mass is conserved in a chemical reaction?
A. Boyle’s law
B. Charles’s law
C. Law of conservation of mass
D. Avogadro’s law
Answer: Law of conservation of mass
Mass is neither created nor destroyed in a chemical reaction.
11. Balance: H₂ + O₂ → H₂O. What is coefficient of H₂?
A. 1
B. 2
C. 3
D. 4
, Answer: 2
Balanced equation: 2H₂ + O₂ → 2H₂O.
12. What is 1 mole equal to?
A. 6.02 × 10²²
B. 6.02 × 10²³
C. 6.02 × 10²⁴
D. 6.02 × 10²⁵
Answer: 6.02 × 10²³
Avogadro’s number defines one mole.
13. Which is the limiting reagent?
A. Excess reactant
B. Reactant that runs out first
C. Catalyst
D. Solvent
Answer: Reactant that runs out first
It determines the maximum product formed.
14. Ideal gas law is expressed as:
A. PV = nRT
B. P = nRT
C. V = nRT
D. PV = RT
Answer: PV = nRT
Relates pressure, volume, moles, and temperature.
15. Increasing temperature at constant volume increases:
A. Volume
B. Pressure
C. Moles
D. Mass
Answer: Pressure
Higher temperature increases kinetic energy and pressure.
16. Which gas law relates pressure and volume inversely?
A. Charles’s law
B. Boyle’s law
C. Avogadro’s law
D. Dalton’s law
Answer: Boyle’s law
Pressure and volume are inversely proportional.
17. Heat absorbed by a system is:
A. Negative
B. Positive
C. Zero
D. Constant
Answer: Positive
Endothermic processes absorb heat.
18. Which process releases heat?
A. Endothermic
