POST UTME EKSU 2022 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 2022 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1
The rate cons\tant (k) of a first-order reaction is given by the equation: k = 2.303/t \log10\( A0/A \). If the half-life of the reaction is 10 minutes, what is the value of k?
Correct A. 0.0693 min^-1
B. 0.693 min^-1
C. 1.386 min^-1
D. 2.303 min^-1

Correct Answer: A

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Question 2
A 0.1 M solution of NaCl is prepared by dissolving 6.0 g of NaCl in 100 mL of water. What is the concentration of Cl^- ions in the solution?
A. 0.1 M
Correct B. 0.2 M
C. 0.3 M
D. 0.4 M

Correct Answer: B

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Question 3
A diagram of a titration setup is shown below. What is the purpose of the burette in this setup?
Correct A. To measure the volume of the titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To separate the titrant and analyte

Correct Answer: A

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Question 4
A 1.0 M solution of HCl is prepared by dissolving 36.5 g of HCl in 100 mL of water. What is the pH of the solution?
A. 0.5
Correct B. 1.0
C. 2.0
D. 3.0

Correct Answer: B

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Question 5
A diagram of a chromatography setup is shown below. What is the purpose of the stationary phase in this setup?
Correct A. To separate the components of the mixture
B. To identify the components of the mixture
C. To measure the concentration of the components
D. To purify the components of the mixture

Correct Answer: A

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Question 6
A sample of an ideal gas is heated at cons\tant volume. Which of the following statements is true about the change in entropy of the gas?
A. The entropy of the gas increases.
Correct B. The entropy of the gas decreases.
C. The entropy of the gas remains cons\tant.
D. The entropy of the gas becomes undefined.

Correct Answer: B

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Question 7
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 8
A 2.0 L flask contains 1.0 atm of He gas at 298 K. What is the pressure of the gas in the flask if it is heated to 373 K?
A. 1.5 atm
B. 2.0 atm
Correct C. 2.5 atm
D. 3.0 atm

Correct Answer: C

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Question 9
A sample of 1.0 g of a non-metallic element has a density of 5.0 g/cm³. What is the volume of the sample in cm³?
A. 0.2 cm³
Correct B. 0.5 cm³
C. 1.0 cm³
D. 2.0 cm³

Correct Answer: B

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Question 10
A 2.0 M solution of HCl is prepared by dissolving 40 g of HCl in 100 mL of water. What is the concentration of the solution in mol/L?
A. 0.4 mol/L
B. 1.0 mol/L
Correct C. 2.0 mol/L
D. 4.0 mol/L

Correct Answer: C

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Question 11
Determine the number of moles of ΔHgS that can be formed from 0.500 mol of Hg(NO3)2 and 0.750 mol of Na2S, given that the reaction is: Hg(NO3)2 + Na2S → ΔHgS + 2NaNO3.
A. 0.250 mol
B. 0.375 mol
Correct C. 0.500 mol
D. 0.750 mol

Correct Answer: C

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Question 12
A 2.50 L sample of a gas at 25°C and 1.00 atm is collected over water at 25°C. If the vapor pressure of water at 25°C is 23.8 torr, what is the partial pressure of the gas?
A. 0.980 atm
B. 0.990 atm
Correct C. 1.00 atm
D. 1.01 atm

Correct Answer: C

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Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of H2O(l) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol?
A. -285.8 kJ/mol
B. -285.9 kJ/mol
Correct C. -286.0 kJ/mol
D. -286.1 kJ/mol

Correct Answer: C

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Question 14
A 0.500 L sample of a 0.100 M solution of NaOH is mixed with a 0.500 L sample of a 0.100 M solution of HCl. 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 15
A 2.50 g sample of a polymer is dissolved in 100.0 mL of a solvent. If the density of the solution is 1.00 g/mL, what is the molar mass of the polymer?
A. 100.0 g/mol
B. 200.0 g/mol
Correct C. 300.0 g/mol
D. 400.0 g/mol

Correct Answer: C

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