POST UTME UNIPORT 2025 Chemistry | Objective

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Question 1 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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 View Details
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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