POST UTME UNIPORT 2025 Chemistry | Objective

Are you preparing for POST UTME UNIPORT exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2025 Chemistry (Objective) questions designed to simulate the real exam environment.

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Question 1
Determine the number of moles of oxygen gas (O2) produced at STP when 2.5 moles of potassium chlorate (KClO3) decompose according to the equation: 2KClO3(s) → 2KCl(s) + 3O2(g).
A. 1.5 moles
B. 2.5 moles
Correct C. 3.75 moles
D. 4.5 moles

Correct Answer: C

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Question 2
A sample of nitrogen gas (N2) has a volume of 2.5 liters at a pressure of 1.5 atm and a temperature of 298 K. Calculate the number of moles of nitrogen gas present.
A. 0.5 moles
Correct B. 1.0 moles
C. 1.5 moles
D. 2.0 moles

Correct Answer: B

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Question 3
A 2.0 M solution of sulfuric acid (H2SO4) has a volume of 1.0 liter. Calculate the number of moles of sulfuric acid present.
A. 0.5 moles
Correct B. 1.0 moles
C. 1.5 moles
D. 2.0 moles

Correct Answer: B

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Question 4
A sample of oxygen gas (O2) has a volume of 3.0 liters at a pressure of 2.0 atm and a temperature of 300 K. Calculate the number of moles of oxygen gas present.
A. 1.0 moles
B. 1.5 moles
Correct C. 2.0 moles
D. 2.5 moles

Correct Answer: C

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Question 5
A 1.0 M solution of sodium hydroxide (NaOH) has a volume of 2.0 liters. Calculate the number of moles of sodium hydroxide present.
A. 0.5 moles
Correct B. 1.0 moles
C. 1.5 moles
D. 2.0 moles

Correct Answer: B

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Question 6
Determine the number of moles of electrons transferred during the electrolysis of 2.5 L of 0.5 M H2SO4.
A. 1.25 mol
B. 2.5 mol
Correct C. 5.0 mol
D. 7.5 mol

Correct Answer: C

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Question 7
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. What is the molar mass of the monomer?
A. 200 g/mol
Correct B. 400 g/mol
C. 500 g/mol
D. 1000 g/mol

Correct Answer: B

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Question 8
A gas occupies a volume of 2.5 L at a pressure of 1 atm and a temperature of 25°C. What is the volume of the gas at a pressure of 3 atm and a temperature of 50°C?
A. 1.25 L
Correct B. 2.5 L
C. 5.0 L
D. 7.5 L

Correct Answer: B

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Question 9
A metal has a density of 8.5 g/cm³ and a volume of 2.5 cm³. What is the mass of the metal?
A. 21.25 g
Correct B. 22.5 g
C. 23.75 g
D. 25.0 g

Correct Answer: B

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Question 10
A solution contains 0.5 M HCl and 0.5 M NaOH. What is the pH of the solution?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 11
In a redox reaction, what is the role of the catalyst in facilitating the reaction?
A. To increase the activation energy of the reaction
Correct B. To decrease the activation energy of the reaction
C. To increase the rate of reaction
D. To decrease the rate of reaction

Correct Answer: B

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Question 12
A solution of 0.1 M NaCl is prepared by dissolving 6.0 g of NaCl in 100 mL of water. What is the concentration of the solution in g/L?
Correct A. 0.6 g/L
B. 6.0 g/L
C. 60 g/L
D. 600 g/L

Correct Answer: A

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Question 13
A sample of 2.5 g of a subs\tance is dissolved in 50 mL of water to give a solution with a pH of 4.5. What is the concentration of the solution in M?
A. 0.1 M
Correct B. 0.5 M
C. 1.0 M
D. 2.0 M

Correct Answer: B

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Question 14
A solution of 0.1 M HCl is prepared by dissolving 3.0 g of HCl in 100 mL of water. What is the concentration of the solution in g/L?
Correct A. 3.0 g/L
B. 30 g/L
C. 300 g/L
D. 3000 g/L

Correct Answer: A

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Question 15
A sample of 5.0 g of a subs\tance is dissolved in 100 mL of water to give a solution with a pH of 7.0. What is the concentration of the solution in M?
A. 0.1 M
B. 0.5 M
Correct C. 1.0 M
D. 2.0 M

Correct Answer: C

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Question 16
A solution of 0.1 M NaOH is prepared by dissolving 4.0 g of NaOH in 100 mL of water. What is the concentration of the solution in g/L?
Correct A. 4.0 g/L
B. 40 g/L
C. 400 g/L
D. 4000 g/L

Correct Answer: A

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Question 17
A sample of 3.0 g of a subs\tance is dissolved in 50 mL of water to give a solution with a pH of 3.0. What is the concentration of the solution in M?
A. 0.1 M
Correct B. 0.5 M
C. 1.0 M
D. 2.0 M

Correct Answer: B

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Question 18
A solution of 0.1 M H2SO4 is prepared by dissolving 6.0 g of H2SO4 in 100 mL of water. What is the concentration of the solution in g/L?
Correct A. 6.0 g/L
B. 60 g/L
C. 600 g/L
D. 6000 g/L

Correct Answer: A

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Question 19
A sample of 4.0 g of a subs\tance is dissolved in 100 mL of water to give a solution with a pH of 5.0. What is the concentration of the solution in M?
A. 0.1 M
B. 0.5 M
Correct C. 1.0 M
D. 2.0 M

Correct Answer: C

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Question 20
The reaction between chlorine gas and potassium iodide is a classic example of a redox reaction. Which of the following best describes the oxidation state of iodine in the product?
A. 0
B. -1
Correct C. +1
D. +5

Correct Answer: C

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Question 21
The entropy change for the following reaction is given by ΔS = 50 J/K. What is the change in entropy for the reverse reaction?
Correct A. -50 J/K
B. 50 J/K
C. 100 J/K
D. -100 J/K

Correct Answer: A

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Question 22
The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100 g, what is the amount remaining after 10 years?
Correct A. 25 g
B. 50 g
C. 75 g
D. 100 g

Correct Answer: A

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Question 23
The reaction between hydrogen gas and oxygen gas is a classic example of a combustion reaction. Which of the following best describes the products of the reaction?
A. H2O and CO2
B. H2O and O2
C. CO and H2O
Correct D. CO2 and H2O

Correct Answer: D

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Question 24
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of H2O?
A. -285.8 kJ/mol
B. -393.5 kJ/mol
Correct C. -241.8 kJ/mol
D. -572.7 kJ/mol

Correct Answer: C

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Question 25
The reaction between sodium hydroxide and hydrochloric acid is a classic example of a neutralization reaction. Which of the following best describes the products of the reaction?
Correct A. NaCl and H2O
B. NaOH and HCl
C. NaCl and NaOH
D. H2O and NaCl

Correct Answer: A

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