POST UTME EKSU 2023 Chemistry | Objective

Are you preparing for POST UTME EKSU exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2023 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1
Determine the solubility of CaF2 in a 0.1 M NaCl solution at 25°C, given that the solubility product cons\tant (Ksp) for CaF2 is 3.9 × 10^-11.
Correct A. 1.0 × 10^-5 M
B. 1.5 × 10^-5 M
C. 2.0 × 10^-5 M
D. 2.5 × 10^-5 M

Correct Answer: A

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Question 2
A 2.50-g sample of a compound containing only carbon and hydrogen is burned in a combustion calorimeter, producing 2.00 L of CO2 and 1.50 L of H2O at 25°C and 1 atm. Calculate the empirical formula of the compound.
A. CH4
Correct B. C2H6
C. C3H8
D. C4H10

Correct Answer: B

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Question 3
A 1.00-L solution of 0.100 M NaCl is mixed with a 1.00-L solution of 0.100 M CaCl2. What is the concentration of Cl- ions in the resulting solution?
A. 0.0500 M
Correct B. 0.0750 M
C. 0.100 M
D. 0.125 M

Correct Answer: B

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Question 4
A 25.0-mL sample of a 0.100 M solution of NaOH is added to a 100.0-mL sample of a 0.100 M solution of HCl. What is the pH of the resulting solution?
A. 1.00
B. 2.00
Correct C. 3.00
D. 4.00

Correct Answer: C

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Question 5
A 1.00-g sample of a compound containing only carbon and hydrogen is burned in a combustion calorimeter, producing 1.50 L of CO2 and 1.00 L of H2O at 25°C and 1 atm. Calculate the molar mass of the compound.
A. 30.0 g/mol
B. 40.0 g/mol
Correct C. 50.0 g/mol
D. 60.0 g/mol

Correct Answer: C

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Question 6
Determine the molar solubility of CaF2 in a 0.1 M NaF solution, given that the solubility product cons\tant (Ksp) for CaF2 is 3.9 × 10^-11.
Correct A. 1.0 × 10^-3 M
B. 1.0 × 10^-4 M
C. 1.0 × 10^-5 M
D. 1.0 × 10^-6 M

Correct Answer: A

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Question 7
A 2.50 g sample of a hydrocarbon is combusted in a bomb calorimeter, relea\sing 12.5 kJ of heat energy. If the molar mass of the hydrocarbon is 140 g/mol, what is the average bond energy of the C-H bonds in the hydrocarbon?
A. 350 kJ/mol
B. 400 kJ/mol
Correct C. 450 kJ/mol
D. 500 kJ/mol

Correct Answer: C

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Question 8
A 0.500 M solution of NaOH is mixed with a 0.500 M solution of HCl. What is the pH of the resulting solution?
A. 1.0
Correct B. 2.0
C. 3.0
D. 4.0

Correct Answer: B

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Question 9
A 1.00 M solution of H2SO4 is mixed with a 1.00 M solution of NaOH. What is the resulting concentration of H2SO4?
A. 0.500 M
Correct B. 0.750 M
C. 1.00 M
D. 1.25 M

Correct Answer: B

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Question 10
A 0.500 M solution of HCl is mixed with a 0.500 M solution of NaOH. What is the resulting concentration of HCl?
A. 0.250 M
B. 0.375 M
C. 0.500 M
Correct D. 0.625 M

Correct Answer: D

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Question 11
Determine the pH of a 0.1 M solution of HCl at 25°C.
Correct A. 1
B. 2
C. 3
D. 4

Correct Answer: A

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Question 12
A 25 mL sample of 0.5 M NaOH is titrated with 0.5 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.025
Correct B. 0.05
C. 0.075
D. 0.1

Correct Answer: B

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Question 13
A solution contains 0.1 M HCl and 0.1 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 14
A 10 mL sample of 0.5 M HCl is mixed with 10 mL of 0.5 M NaOH. What is the pH of the resulting solution?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 15
A 25 mL sample of 0.5 M HCl is titrated with 0.5 M NaOH. Calculate the number of moles of NaOH required to reach the equivalence point.
A. 0.025
Correct B. 0.05
C. 0.075
D. 0.1

Correct Answer: B

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Question 16
Determine the pH of a solution containing 0.1 M HCl and 0.1 M NaOH.
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 17
A sample of a non-metallic oxide is found to have a mass of 25.0 g and a volume of 2.5 L. Calculate the molar mass of the oxide.
A. 50 g/mol
B. 75 g/mol
Correct C. 100 g/mol
D. 125 g/mol

Correct Answer: C

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Question 18
A gas at 25°C and 1 atm is compressed to 2 atm. What is the new volume of the gas?
A. 1 L
B. 2 L
Correct C. 4 L
D. 8 L

Correct Answer: C

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Question 19
A solution of 0.1 M HCl is mixed with a solution of 0.1 M NaOH. What is the resulting pH?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 20
A sample of a metal is found to have a mass of 50.0 g and a volume of 5.0 L. Calculate the molar mass of the metal.
A. 10 g/mol
B. 20 g/mol
Correct C. 30 g/mol
D. 40 g/mol

Correct Answer: C

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