Practice post utme uniosun chemistry 2025 Past Questions

Question 1

A sample of an ideal gas is heated at cons\tant volume. Which of the following statements is true about the change in the gas's properties?

A. The gas expands and its pressure increases.

B. The gas contracts and its pressure decreases.

Correct C. The gas expands and its pressure remains cons\tant.

D. The gas contracts and its pressure remains cons\tant.

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 2

A polymer is formed by the condensation reaction of two monomers. Which of the following is a characteristic of the polymer formed?

A. The polymer has a high melting point.

B. The polymer is soluble in water.

C. The polymer has a high tensile strength.

Correct D. The polymer is biodegradable.

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 3

A chemical reaction is at equilibrium. Which of the following statements is true about the reaction?

A. The reaction is proceeding in the forward direction.

B. The reaction is proceeding in the reverse direction.

Correct C. The reaction is at a steady state.

D. The reaction is not at equilibrium.

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 4

A sample of water is contaminated with a pollu\tant. Which of the following methods can be used to remove the pollu\tant?

A. Distillation

B. Filtration

C. Adsorption

Correct D. All of the above

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 5

A solution is prepared by dissolving a solute in a solvent. Which of the following statements is true about the solution?

Correct A. The solution is homogeneous.

B. The solution is heterogeneous.

C. The solution is isotonic.

D. The solution is hypotonic.

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 6

A 0.1 M solution of a weak base, B, has a pH of 8.5. Calculate the value of Kb for the base.

Correct A. 1.3 × 10^-5

B. 1.3 × 10^-4

C. 1.3 × 10^-3

D. 1.3 × 10^-2

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 7

A 2.0 M solution of HCl is mixed with a 2.0 M solution of NaOH. What is the pH of the resulting solution?

A. 0.5

Correct B. 1.0

C. 1.5

D. 2.0

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 8

A 0.1 M solution of a weak acid, HA, has a pH of 4.2. Calculate the value of Ka for the acid.

Correct A. 1.3 × 10^-5

B. 1.3 × 10^-4

C. 1.3 × 10^-3

D. 1.3 × 10^-2

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 9

A 2.0 M solution of H2SO4 is mixed with a 2.0 M solution of NaOH. What is the pH of the resulting solution?

A. 0.5

Correct B. 1.0

C. 1.5

D. 2.0

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 10

A 0.1 M solution of a weak base, B, has a pH of 8.5. Calculate the value of Kb for the base.

Correct A. 1.3 × 10^-5

B. 1.3 × 10^-4

C. 1.3 × 10^-3

D. 1.3 × 10^-2

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 11

The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of copper in the reac\tant and product?

A. Cu(II) in reac\tant and Cu(0) in product

Correct B. Cu(0) in reac\tant and Cu(II) in product

C. Cu(II) in reac\tant and Cu(I) in product

D. Cu(I) in reac\tant and Cu(II) in product

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 12

A 0.1 M solution of HCl is electrolyzed u\sing a platinum electrode. What is the mass of chlorine gas liberated at the anode after 2 hours?

A. 0.5 g

B. 1.0 g

Correct C. 1.5 g

D. 2.0 g

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 13

The reaction of methane with chlorine gas is represented by the equation: CH4(g) + Cl2(g) → CH3Cl(g) + HCl(g). What is the type of reaction?

A. Combustion reaction

Correct B. Substitution reaction

C. Addition reaction

D. Oxidation-reduction reaction

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 14

A 1.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. What is the pH of the resulting solution?

Correct A. 7

B. 8

C. 9

D. 10

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 15

The reaction of sulfur dioxide with oxygen gas is represented by the equation: 2SO2(g) + O2(g) → 2SO3(g). What is the type of reaction?

A. Combustion reaction

Correct B. Oxidation-reduction reaction

C. Addition reaction

D. Substitution reaction

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 16

The reaction of nitrogen dioxide with water is a classic example of a redox reaction. Write the balanced chemical equation for the reaction and identify the oxidizing and reducing agents.

Correct A. NO2 + H2O → HNO3 + NO

B. NO2 + H2O → HNO3 + H2

C. NO2 + H2O → HNO3 + O2

D. NO2 + H2O → HNO3 + NO2

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 17

A 0.5 M solution of sulfuric acid (H2SO4) is mixed with a 0.2 M solution of sodium hydroxide (NaOH). Determine the concentration of the resulting solution after the reaction is complete.

Correct A. 0.3 M

B. 0.4 M

C. 0.5 M

D. 0.6 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 18

A 2.0 g sample of a non-metallic oxide is heated in a stream of carbon dioxide gas. The resulting gas is collected and found to have a volume of 2.5 L at 25°C and 1 atm. What is the molar mass of the oxide?

A. 50 g/mol

Correct B. 60 g/mol

C. 70 g/mol

D. 80 g/mol

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 19

A solution of hydrogen peroxide (H2O2) is decomposed by a catalyst to produce oxygen gas. The reaction is first-order with respect to hydrogen peroxide. If the initial concentration of hydrogen peroxide is 0.1 M and the half-life of the reaction is 10 minutes, what is the concentration of hydrogen peroxide after 20 minutes?

Correct A. 0.05 M

B. 0.025 M

C. 0.01 M

D. 0.005 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 20

A 1.0 L sample of a gas at 25°C and 1 atm is collected and found to have a mass of 2.5 g. What is the molar mass of the gas?

A. 20 g/mol

B. 30 g/mol

Correct C. 40 g/mol

D. 50 g/mol

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 21

A 0.5 M solution of sodium chloride (NaCl) is mixed with a 0.2 M solution of silver nitrate (AgNO3). Determine the concentration of the resulting solution after the reaction is complete.

Correct A. 0.3 M

B. 0.4 M

C. 0.5 M

D. 0.6 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 22

A 2.0 g sample of a non-metallic oxide is heated in a stream of carbon dioxide gas. The resulting gas is collected and found to have a volume of 2.5 L at 25°C and 1 atm. What is the molar mass of the oxide?

A. 50 g/mol

Correct B. 60 g/mol

C. 70 g/mol

D. 80 g/mol

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 23

A solution of hydrogen peroxide (H2O2) is decomposed by a catalyst to produce oxygen gas. The reaction is first-order with respect to hydrogen peroxide. If the initial concentration of hydrogen peroxide is 0.1 M and the half-life of the reaction is 10 minutes, what is the concentration of hydrogen peroxide after 20 minutes?

Correct A. 0.05 M

B. 0.025 M

C. 0.01 M

D. 0.005 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 24

Determine the pH of a 0.1 M solution of HCl.

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 25

A sample of CO2 gas at 25°C and 1 atm is collected over water. Calculate the partial pressure of CO2.

A. 0.9 atm

Correct B. 0.95 atm

C. 1.05 atm

D. 1.1 atm

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

POST UTME UNIOSUN 2025 Chemistry | Objective

Master the Exam!

Help others prepare! Share this practice hub: