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CHEM-110: CHEMISTRY & BIOCHEMISTRY LATEST
2025/ 2026 TEST BANK| COMPLETE 350 REAL
EXAM QUESTIONS AND CORRECT ANSWERS WITH
WELL-ELABORATED RATIONALES/ GRADED A+
Atomic Structure & Periodic Trends
Question 1
Which subatomic particle determines the identity of an element?
A. Neutron
B. Electron
C. Proton
D. Positron
Answer: C. Proton
Rationale: The number of protons (atomic number) uniquely identifies
an element.
Question 2
atom with atomic number 8 contains:
A. 8 neutrons only
C. 8 electrons and 8 neutrons only
D. 16 protons
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Answer: B. 8 protons
Rationale: Atomic number equals the number of protons in the
nucleus.
Question 3
Which type of bond involves the sharing of electrons?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Metallic bond
Answer: C. Covalent bond
Rationale: Covalent bonds form when atoms share one or more pairs
of electrons.
Question 4
Which element is most electronegative?
A. Sodium
B. Chlorine
C. Fluorine
D. Oxygen
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Answer: C. Fluorine
Rationale: Fluorine has the highest electronegativity on the periodic
table.
Question 5
What is the molar mass of H₂O?
A. 16 g/mol
B. 18 g/mol
C. 20 g/mol
D. 22 g/mol
Answer: B. 18 g/mol
Rationale: Hydrogen contributes 2 g/mol and oxygen contributes 16
g/mol, totaling 18 g/mol.
Question 61
How many moles are present in 36 g of water (H₂O)?
A. 1 mol
B. 2 mol
C. 3 mol
D. 4 mol
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Answer: B. 2 mol
Rationale: Moles = Mass ÷ Molar Mass = 36 g ÷ 18 g/mol = 2 mol.
Question 62
How many molecules are present in 1 mole of CO₂?
A. 6.022 × 10²³
B. 3.011 × 10²³
C. 1.204 × 10²⁴
D. 6.022 × 10²²
Answer: A. 6.022 × 10²³
Question 63
The limiting reactant is:
A. The product formed first
B. The reactant consumed first
C. The catalyst used
D. The excess reactant
Answer: B. The reactant consumed first
pg. 4
CHEM-110: CHEMISTRY & BIOCHEMISTRY LATEST
2025/ 2026 TEST BANK| COMPLETE 350 REAL
EXAM QUESTIONS AND CORRECT ANSWERS WITH
WELL-ELABORATED RATIONALES/ GRADED A+
Atomic Structure & Periodic Trends
Question 1
Which subatomic particle determines the identity of an element?
A. Neutron
B. Electron
C. Proton
D. Positron
Answer: C. Proton
Rationale: The number of protons (atomic number) uniquely identifies
an element.
Question 2
atom with atomic number 8 contains:
A. 8 neutrons only
C. 8 electrons and 8 neutrons only
D. 16 protons
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Answer: B. 8 protons
Rationale: Atomic number equals the number of protons in the
nucleus.
Question 3
Which type of bond involves the sharing of electrons?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Metallic bond
Answer: C. Covalent bond
Rationale: Covalent bonds form when atoms share one or more pairs
of electrons.
Question 4
Which element is most electronegative?
A. Sodium
B. Chlorine
C. Fluorine
D. Oxygen
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Answer: C. Fluorine
Rationale: Fluorine has the highest electronegativity on the periodic
table.
Question 5
What is the molar mass of H₂O?
A. 16 g/mol
B. 18 g/mol
C. 20 g/mol
D. 22 g/mol
Answer: B. 18 g/mol
Rationale: Hydrogen contributes 2 g/mol and oxygen contributes 16
g/mol, totaling 18 g/mol.
Question 61
How many moles are present in 36 g of water (H₂O)?
A. 1 mol
B. 2 mol
C. 3 mol
D. 4 mol
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Answer: B. 2 mol
Rationale: Moles = Mass ÷ Molar Mass = 36 g ÷ 18 g/mol = 2 mol.
Question 62
How many molecules are present in 1 mole of CO₂?
A. 6.022 × 10²³
B. 3.011 × 10²³
C. 1.204 × 10²⁴
D. 6.022 × 10²²
Answer: A. 6.022 × 10²³
Question 63
The limiting reactant is:
A. The product formed first
B. The reactant consumed first
C. The catalyst used
D. The excess reactant
Answer: B. The reactant consumed first
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