CHEM 103 MODULE 3 COMPLETE
2026/2027 PRACTICE EXAM (1–200
QUESTIONS WITH ANSWERS &
RATIONALES)
CHEM 103 Module 3 – 2026/2027 Practice Exam
1. Which of the following is a physical property?
A. Flammability
B. Reactivity with acid
C. Melting point
D. Oxidation state
Answer: C. Melting point
Melting point can be observed without changing the substance’s
chemical identity.
2. Which of the following is a chemical change?
A. Dissolving sugar in water
B. Burning wood
C. Melting ice
D. Boiling water
Answer: B. Burning wood
Burning produces new substances (CO₂, ash) indicating a chemical
reaction.
3. Which particle is positively charged?
A. Electron
B. Proton
C. Neutron
D. Photon
,Answer: B. Proton
Protons carry a positive charge in the nucleus.
4. The atomic number of an element equals the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Answer: B. Protons
Atomic number defines the element and equals the number of protons.
5. Which of the following represents a compound?
A. O₂
B. H₂O
C. N₂
D. He
Answer: B. H₂O
A compound contains two or more different elements chemically
bonded.
6. What is the molar mass of CO₂?
A. 12 g/mol
B. 16 g/mol
C. 44 g/mol
D. 28 g/mol
Answer: C. 44 g/mol
12 (C) + 16×2 (O) = 44 g/mol.
7. Which type of bond is formed by sharing electrons?
A. Ionic
B. Covalent
C. Metallic
D. Hydrogen
,Answer: B. Covalent
Covalent bonds involve sharing of electron pairs between atoms.
8. Which element is in Group 2 of the periodic table?
A. Sodium (Na)
B. Calcium (Ca)
C. Chlorine (Cl)
D. Oxygen (O)
Answer: B. Calcium (Ca)
Group 2 contains alkaline earth metals.
9. Which of the following is an example of a heterogeneous
mixture?
A. Salt water
B. Air
C. Oil and water
D. Sugar solution
Answer: C. Oil and water
Heterogeneous mixtures have visibly distinct components.
10. Which gas law relates pressure and volume at constant
temperature?
A. Charles’s Law
B. Boyle’s Law
C. Avogadro’s Law
D. Ideal Gas Law
Answer: B. Boyle’s Law
Pressure and volume are inversely proportional at constant
temperature.
11. Which particle determines chemical reactivity?
A. Neutron
B. Proton
, C. Electron
D. Nucleus
Answer: C. Electron
Valence electrons participate in chemical bonding and reactions.
12. Which of the following is a noble gas?
A. Nitrogen (N)
B. Helium (He)
C. Hydrogen (H)
D. Oxygen (O)
Answer: B. Helium (He)
Noble gases are in Group 18 and are chemically inert.
13. Which term describes the amount of matter in an object?
A. Mass
B. Weight
C. Volume
D. Density
Answer: A. Mass
Mass is independent of gravity and measures matter quantity.
14. What is the oxidation state of oxygen in H₂O?
A. +1
B. -1
C. -2
D. 0
Answer: C. -2
Oxygen usually has a -2 oxidation state in compounds.
15. Which of the following is a strong acid?
A. HCl
B. CH₃COOH
2026/2027 PRACTICE EXAM (1–200
QUESTIONS WITH ANSWERS &
RATIONALES)
CHEM 103 Module 3 – 2026/2027 Practice Exam
1. Which of the following is a physical property?
A. Flammability
B. Reactivity with acid
C. Melting point
D. Oxidation state
Answer: C. Melting point
Melting point can be observed without changing the substance’s
chemical identity.
2. Which of the following is a chemical change?
A. Dissolving sugar in water
B. Burning wood
C. Melting ice
D. Boiling water
Answer: B. Burning wood
Burning produces new substances (CO₂, ash) indicating a chemical
reaction.
3. Which particle is positively charged?
A. Electron
B. Proton
C. Neutron
D. Photon
,Answer: B. Proton
Protons carry a positive charge in the nucleus.
4. The atomic number of an element equals the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Answer: B. Protons
Atomic number defines the element and equals the number of protons.
5. Which of the following represents a compound?
A. O₂
B. H₂O
C. N₂
D. He
Answer: B. H₂O
A compound contains two or more different elements chemically
bonded.
6. What is the molar mass of CO₂?
A. 12 g/mol
B. 16 g/mol
C. 44 g/mol
D. 28 g/mol
Answer: C. 44 g/mol
12 (C) + 16×2 (O) = 44 g/mol.
7. Which type of bond is formed by sharing electrons?
A. Ionic
B. Covalent
C. Metallic
D. Hydrogen
,Answer: B. Covalent
Covalent bonds involve sharing of electron pairs between atoms.
8. Which element is in Group 2 of the periodic table?
A. Sodium (Na)
B. Calcium (Ca)
C. Chlorine (Cl)
D. Oxygen (O)
Answer: B. Calcium (Ca)
Group 2 contains alkaline earth metals.
9. Which of the following is an example of a heterogeneous
mixture?
A. Salt water
B. Air
C. Oil and water
D. Sugar solution
Answer: C. Oil and water
Heterogeneous mixtures have visibly distinct components.
10. Which gas law relates pressure and volume at constant
temperature?
A. Charles’s Law
B. Boyle’s Law
C. Avogadro’s Law
D. Ideal Gas Law
Answer: B. Boyle’s Law
Pressure and volume are inversely proportional at constant
temperature.
11. Which particle determines chemical reactivity?
A. Neutron
B. Proton
, C. Electron
D. Nucleus
Answer: C. Electron
Valence electrons participate in chemical bonding and reactions.
12. Which of the following is a noble gas?
A. Nitrogen (N)
B. Helium (He)
C. Hydrogen (H)
D. Oxygen (O)
Answer: B. Helium (He)
Noble gases are in Group 18 and are chemically inert.
13. Which term describes the amount of matter in an object?
A. Mass
B. Weight
C. Volume
D. Density
Answer: A. Mass
Mass is independent of gravity and measures matter quantity.
14. What is the oxidation state of oxygen in H₂O?
A. +1
B. -1
C. -2
D. 0
Answer: C. -2
Oxygen usually has a -2 oxidation state in compounds.
15. Which of the following is a strong acid?
A. HCl
B. CH₃COOH
