POST UTME EKSU 2021 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 2021 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

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

Correct Answer: D

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Question 2
A 2.5 g sample of a non-metallic oxide is dissolved in 50 cm³ of water. If the resulting solution has a pH of 3.5, what is the molar mass of the oxide?
A. 100 g/mol
B. 200 g/mol
Correct C. 300 g/mol
D. 400 g/mol

Correct Answer: C

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Question 3
A diagram of a titration apparatus is shown below.
A. The burette contains the acid.
B. The beaker contains the acid.
Correct C. The burette contains the base.
D. The beaker contains the base.

Correct Answer: C

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Question 4
A 1.0 M solution of NaOH is titrated with a 1.0 M solution of HCl. If 25 cm³ of the HCl solution is required to reach the equivalence point, what is the volume of the NaOH solution required to reach the equivalence point?
A. 25 cm³
Correct B. 50 cm³
C. 75 cm³
D. 100 cm³

Correct Answer: B

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Question 5
A diagram of a gas apparatus is shown below.
Correct A. The flask contains the gas.
B. The tube contains the gas.
C. The flask contains the liquid.
D. The tube contains the liquid.

Correct Answer: A

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Question 6
The reaction of cyclohexane with bromine in the presence of light produces a mixture of 1,2-dibromocyclohexane and 1,4-dibromocyclohexane. What is the major product of this reaction?
A. 1,2-dibromocyclohexane
Correct B. 1,4-dibromocyclohexane
C. cis-1,2-dibromocyclohexane
D. trans-1,2-dibromocyclohexane

Correct Answer: B

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Question 7
A solution of 0.500 M HCl is titrated with 0.500 M NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?
A. 2.00
B. 3.00
Correct C. 4.00
D. 5.00

Correct Answer: C

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Question 8
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of combustion of 1.00 mol of C6H12O6(s)?
A. -2800 kJ
B. -2900 kJ
Correct C. -3000 kJ
D. -3100 kJ

Correct Answer: C

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Question 9
A sample of nitrogen gas is collected over water at 25.0°C and 1.00 atm. What is the partial pressure of the nitrogen gas?
A. 0.950 atm
B. 0.975 atm
Correct C. 1.00 atm
D. 1.05 atm

Correct Answer: C

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Question 10
A diagram of the apparatus used to determine the molar mass of a gas is shown below. What is the purpose of the U-tube manometer?
Correct A. to measure the pressure of the gas
B. to measure the volume of the gas
C. to measure the temperature of the gas
D. to measure the molar mass of the gas

Correct Answer: A

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Question 11
Determine the s\tandard Gibbs free energy change (ΔG°) for the reaction: 2Ag+(aq) + 2Cl-(aq) → 2AgCl(s) at 298 K, given that the s\tandard enthalpy change (ΔH°) is -364.7 kJ/mol and the s\tandard entropy change (ΔS°) is -173.5 J/mol·K.
A. -364.7 kJ/mol
B. -173.5 kJ/mol
Correct C. -364.7 kJ/mol - 298 K × 173.5 J/mol·K
D. -364.7 kJ/mol + 298 K × 173.5 J/mol·K

Correct Answer: C

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Question 12
A 0.500 M solution of HCl(aq) is mixed with a 0.500 M solution of NaOH(aq) in a 1.00 L flask. What is the pH of the resulting solution?
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 13
A metal (X) has a s\tandard reduction potential of +0.80 V. What is the s\tandard reduction potential of the metal ion \( X+ \)?
Correct A. -0.80 V
B. +0.80 V
C. +1.60 V
D. +2.00 V

Correct Answer: A

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Question 14
A sample of a gas at 25°C and 1.00 atm is compressed to 2.00 atm at cons\tant temperature. What is the new volume of the gas?
A. 0.500 L
B. 1.00 L
Correct C. 2.00 L
D. 4.00 L

Correct Answer: C

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Question 15
A 1.00 M solution of H2SO4(aq) is mixed with a 1.00 M solution of NaOH(aq) in a 1.00 L flask. What is the concentration of the resulting solution?
A. 0.500 M
B. 1.00 M
Correct C. 1.50 M
D. 2.00 M

Correct Answer: C

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Question 16
A 2.50 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 1.75 g, calculate the molar mass of the metal carbonate.
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 17
A 1.0 L sample of a gas at 25°C and 1 atm is compressed to 0.5 L at the same temperature. What is the new pressure?
A. 2 atm
Correct B. 4 atm
C. 6 atm
D. 8 atm

Correct Answer: B

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Question 18
A 250 mL sample of a 0.5 M solution of NaOH is mixed with 250 mL of a 0.5 M solution of HCl. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 19
A 2.0 g sample of a metal is heated in air to produce a metal oxide. If the mass of the metal oxide produced is 3.5 g, calculate the percentage yield of the reaction.
A. 50%
B. 60%
Correct C. 70%
D. 80%

Correct Answer: C

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Question 20
A 1.0 L sample of a gas at 25°C and 1 atm is heated to 50°C at cons\tant volume. What is the new pressure?
A. 2 atm
B. 4 atm
Correct C. 6 atm
D. 8 atm

Correct Answer: C

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Question 21
Determine the molar solubility of BaSO4 in 0.1 M Na2SO4 solution, given that the solubility product cons\tant (Ksp) for BaSO4 is 1.1 x 10^-10.
Correct A. 1.0 x 10^-5 M
B. 1.0 x 10^-6 M
C. 1.0 x 10^-7 M
D. 1.0 x 10^-8 M

Correct Answer: A

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Question 22
A 25.0 mL sample of 0.500 M NaOH is titrated with 0.100 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.0125 mol
Correct B. 0.0250 mol
C. 0.0375 mol
D. 0.0500 mol

Correct Answer: B

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Question 23
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the repeating unit.
A. 100 g/mol
B. 200 g/mol
Correct C. 500 g/mol
D. 1000 g/mol

Correct Answer: C

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Question 24
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C6H12O6(s).
A. -2800 kJ
B. -2900 kJ
Correct C. -3000 kJ
D. -3100 kJ

Correct Answer: C

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Question 25
A 1.00 L sample of 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the pH of the solution at the equivalence point.
A. 7.00
Correct B. 8.00
C. 9.00
D. 10.0

Correct Answer: B

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