CHEM103 General Chemistry I W/ Lab Final
Assessment Latest Updated Graded A+
Question 1: Atomic Structure
Which of the following has the greatest number of neutrons?
A.
B.
C.
D.
Rationale: Neutrons = mass number – atomic number. Neon-20 has 10 protons and 10
neutrons, the highest among the options.
Question 2: Stoichiometry
How many grams of NaOH are required to neutralize 0.50 mol of HCl?
A. 10 g
B. 20 g
B. 40 g
C. 80 g
Rationale: Reaction: NaOH + HCl → NaCl + H₂O. 1:1 mol ratio. Molar mass NaOH = 40
g/mol. g.
Question 3: Chemical Bonding
Which molecule exhibits hydrogen bonding?
A. CH₄
B. CO₂
C. NH₃
C. CCl₄
Rationale: Hydrogen bonding occurs when H is bonded to N, O, or F. NH₃ qualifies.
Question 4: Thermochemistry
The combustion of methane releases 890 kJ/mol. What is the enthalpy change for
burning 2 mol CH₄?
A. –445 kJ
B. –1780 kJ
B. +890 kJ
C. +1780 kJ
Rationale: Exothermic reaction. Multiply by 2 mol → –1780 kJ.
Question 5: Solutions
What is the molarity of a solution prepared by dissolving 10 g NaOH in 250 mL water?
A. 0.1 M
B. 1.0 M
B. 2.0 M
C. 4.0 M
,Rationale: Moles NaOH = . Volume = 0.25 L. M = .
Question 6: Equilibrium
For the reaction , increasing pressure will:
A. Shift equilibrium left
B. Shift equilibrium right
B. No effect
C. Decrease rate
Rationale: Fewer gas molecules on product side (2 vs 4). Higher pressure favors NH₃
formation.
Question 7: Acid-Base
Which of the following is a weak acid?
A. HCl
B. HNO₃
C. CH₃COOH
C. H₂SO₄
Rationale: Acetic acid is weak; others are strong acids.
Question 8: Gas Laws
At constant temperature, if the volume of a gas is halved, the pressure will:
A. Double
B. Halve
C. Stay the same
D. Decrease slightly
Rationale: Boyle’s Law: .
Question 9: Periodic Trends
Which element has the highest electronegativity?
A. Oxygen
B. Nitrogen
C. Fluorine
C. Chlorine
Rationale: Fluorine is the most electronegative element.
Question 10: Redox
In the reaction , which species is oxidized?
A. Cu²⁺
B. Zn
B. Cu
C. Zn²⁺
Rationale: Zn loses electrons → oxidation.
Question 11: Solutions
Which solution has the highest boiling point elevation?
A. 0.1 M NaCl
, B. 0.1 M glucose
C. 0.1 M CaCl₂
C. 0.1 M urea
Rationale: Colligative property depends on . CaCl₂ dissociates into 3 particles.
Question 12: Thermodynamics
ΔG is negative when:
A. Reaction is non-spontaneous
B. Reaction is spontaneous
B. Reaction is at equilibrium
C. Reaction absorbs energy
Rationale: Negative Gibbs free energy = spontaneous.
Question 13: Nuclear Chemistry
Which radiation has the greatest penetrating power?
A. Alpha
B. Beta
C. Gamma
C. Neutron
Rationale: Gamma rays penetrate most deeply.
Question 14: Stoichiometry
How many liters of O₂ at STP are needed to burn 2 mol CH₄?
A. 22.4 L
B. 44.8 L
C. 89.6 L
C. 179.2 L
Rationale: CH₄ + 2O₂ → CO₂ + 2H₂O. Needs 4 mol O₂. At STP, 1 mol = 22.4 L → 4 ×
22.4 = 89.6 L.
Question 15: Acids/Bases
pH of 0.01 M HCl is:
A. 1
B. 2
B. 3
C. 4
Rationale: Strong acid. pH = –log[H⁺] = –log(0.01) = 2.
Question 16: Bonding
Which compound is ionic?
A. CO₂
B. NH₃
C. NaCl
C. CH₄
Rationale: NaCl is ionic; others are covalent.
Assessment Latest Updated Graded A+
Question 1: Atomic Structure
Which of the following has the greatest number of neutrons?
A.
B.
C.
D.
Rationale: Neutrons = mass number – atomic number. Neon-20 has 10 protons and 10
neutrons, the highest among the options.
Question 2: Stoichiometry
How many grams of NaOH are required to neutralize 0.50 mol of HCl?
A. 10 g
B. 20 g
B. 40 g
C. 80 g
Rationale: Reaction: NaOH + HCl → NaCl + H₂O. 1:1 mol ratio. Molar mass NaOH = 40
g/mol. g.
Question 3: Chemical Bonding
Which molecule exhibits hydrogen bonding?
A. CH₄
B. CO₂
C. NH₃
C. CCl₄
Rationale: Hydrogen bonding occurs when H is bonded to N, O, or F. NH₃ qualifies.
Question 4: Thermochemistry
The combustion of methane releases 890 kJ/mol. What is the enthalpy change for
burning 2 mol CH₄?
A. –445 kJ
B. –1780 kJ
B. +890 kJ
C. +1780 kJ
Rationale: Exothermic reaction. Multiply by 2 mol → –1780 kJ.
Question 5: Solutions
What is the molarity of a solution prepared by dissolving 10 g NaOH in 250 mL water?
A. 0.1 M
B. 1.0 M
B. 2.0 M
C. 4.0 M
,Rationale: Moles NaOH = . Volume = 0.25 L. M = .
Question 6: Equilibrium
For the reaction , increasing pressure will:
A. Shift equilibrium left
B. Shift equilibrium right
B. No effect
C. Decrease rate
Rationale: Fewer gas molecules on product side (2 vs 4). Higher pressure favors NH₃
formation.
Question 7: Acid-Base
Which of the following is a weak acid?
A. HCl
B. HNO₃
C. CH₃COOH
C. H₂SO₄
Rationale: Acetic acid is weak; others are strong acids.
Question 8: Gas Laws
At constant temperature, if the volume of a gas is halved, the pressure will:
A. Double
B. Halve
C. Stay the same
D. Decrease slightly
Rationale: Boyle’s Law: .
Question 9: Periodic Trends
Which element has the highest electronegativity?
A. Oxygen
B. Nitrogen
C. Fluorine
C. Chlorine
Rationale: Fluorine is the most electronegative element.
Question 10: Redox
In the reaction , which species is oxidized?
A. Cu²⁺
B. Zn
B. Cu
C. Zn²⁺
Rationale: Zn loses electrons → oxidation.
Question 11: Solutions
Which solution has the highest boiling point elevation?
A. 0.1 M NaCl
, B. 0.1 M glucose
C. 0.1 M CaCl₂
C. 0.1 M urea
Rationale: Colligative property depends on . CaCl₂ dissociates into 3 particles.
Question 12: Thermodynamics
ΔG is negative when:
A. Reaction is non-spontaneous
B. Reaction is spontaneous
B. Reaction is at equilibrium
C. Reaction absorbs energy
Rationale: Negative Gibbs free energy = spontaneous.
Question 13: Nuclear Chemistry
Which radiation has the greatest penetrating power?
A. Alpha
B. Beta
C. Gamma
C. Neutron
Rationale: Gamma rays penetrate most deeply.
Question 14: Stoichiometry
How many liters of O₂ at STP are needed to burn 2 mol CH₄?
A. 22.4 L
B. 44.8 L
C. 89.6 L
C. 179.2 L
Rationale: CH₄ + 2O₂ → CO₂ + 2H₂O. Needs 4 mol O₂. At STP, 1 mol = 22.4 L → 4 ×
22.4 = 89.6 L.
Question 15: Acids/Bases
pH of 0.01 M HCl is:
A. 1
B. 2
B. 3
C. 4
Rationale: Strong acid. pH = –log[H⁺] = –log(0.01) = 2.
Question 16: Bonding
Which compound is ionic?
A. CO₂
B. NH₃
C. NaCl
C. CH₄
Rationale: NaCl is ionic; others are covalent.
