POST UTME CRAWFORD UNIVERSITY 2020 Chemistry | Objective

Are you preparing for POST UTME CRAWFORD UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2020 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 25 mL sample of 0.5 M NaOH is titrated with 0.5 M HCl. What is the pH of the solution after the addition of 15 mL of HCl?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 3
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 4
A 10 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 5 mL of NaOH?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 5
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution after the addition of 10 mL of 0.1 M HCl?
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 6
The atomic radius of a metal atom is 200 pm. If the electron cloud is assumed to be spherical, calculate the volume of the electron cloud in cubic meters.
Correct A. 1.33 \times 10^{-28} m^3
B. 1.33 \times 10^{-27} m^3
C. 1.33 \times 10^{-29} m^3
D. 1.33 \times 10^{-30} m^3

Correct Answer: A

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Question 7
A metal oxide has the formula M2O3. If the molar mass of the metal is 50 g/mol and the molar mass of oxygen is 16 g/mol, calculate the mass of the metal oxide in grams per mole.
A. 196 g/mol
B. 198 g/mol
Correct C. 200 g/mol
D. 202 g/mol

Correct Answer: C

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Question 8
A gas at 25°C and 1 atm is compressed to 2 atm. Calculate the change in entropy for the gas u\sing the ideal gas equation.
A. -1.05 J/K
Correct B. -1.10 J/K
C. -1.15 J/K
D. -1.20 J/K

Correct Answer: B

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Question 9
A solution of 2 M NaOH is mixed with a solution of 1 M HCl. Calculate the pH of the resulting solution.
Correct A. 1.00
B. 2.00
C. 3.00
D. 4.00

Correct Answer: A

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Question 10
A sample of 1.0 g of a metal is heated to 1000°C. If the specific heat capacity of the metal is 0.1 J/g°C, calculate the energy required to heat the metal.
A. 100 J
B. 200 J
Correct C. 300 J
D. 400 J

Correct Answer: C

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Question 11
A 0.1 M solution of NaCl is prepared by dissolving 2.5 g of NaCl in 100 mL of water. What is the concentration of Na+ ions in the solution?
A. 0.05 M
Correct B. 0.1 M
C. 0.2 M
D. 0.25 M

Correct Answer: B

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Question 12
The rate cons\tant (k) for a first-order reaction is 0.05 min^-1. If the initial concentration of the reac\tant is 0.1 M, what is the concentration after 10 minutes?
Correct A. 0.01 M
B. 0.05 M
C. 0.1 M
D. 0.2 M

Correct Answer: A

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Question 13
A 2.0 M solution of HCl is prepared by dissolving 40 g of HCl in 100 mL of water. What is the pH of the solution?
Correct A. 0
B. 1
C. 2
D. 3

Correct Answer: A

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Question 14
A 1.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 100 mL of water. What is the concentration of OH^- ions in the solution?
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 15
A 0.1 M solution of H2SO4 is prepared by dissolving 10 g of H2SO4 in 100 mL of water. What is the concentration of H^+ ions in the solution?
A. 0.05 M
Correct B. 0.1 M
C. 0.2 M
D. 0.25 M

Correct Answer: B

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Question 16
Determine the s\tandard electrode potential of the cell represented by the following reaction: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O. Given that the s\tandard electrode potential of the MnO4-/Mn2+ couple is +1.23 V.
A. +1.23 V
B. +1.38 V
Correct C. +1.53 V
D. +1.68 V

Correct Answer: C

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Question 17
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. Calculate the pH of the solution after 25 mL of HCl has been added.
A. 7.00
Correct B. 7.25
C. 7.50
D. 8.00

Correct Answer: B

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Question 18
The rate cons\tant (k) of a first-order reaction is 0.05 min-1. Calculate the half-life of the reaction.
A. 1.38 min
Correct B. 2.76 min
C. 4.14 min
D. 5.52 min

Correct Answer: B

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Question 19
A sample of a gas at 25°C and 1 atm is found to have a volume of 2.5 L. Calculate the number of moles of the gas present.
A. 0.05 mol
Correct B. 0.10 mol
C. 0.15 mol
D. 0.20 mol

Correct Answer: B

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Question 20
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. Calculate the pH of the solution after 20 mL of NaOH has been added.
A. 1.00
B. 2.00
Correct C. 3.00
D. 4.00

Correct Answer: C

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Question 21
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, what is the value of the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^-1?
A. 1.0 x 10^6 s^-1
B. 1.0 x 10^7 s^-1
Correct C. 1.0 x 10^8 s^-1
D. 1.0 x 10^9 s^-1

Correct Answer: C

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Question 22
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. If 20 mL of HCl is added, what is the pH of the solution?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 23
A metal (M) reacts with oxygen to form a basic oxide. If the reaction is: 4M + 3O2 → 2M2O3, what is the oxidation state of M in the product?
Correct A. +3
B. +2
C. +1
D. -1

Correct Answer: A

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Question 24
A diagram of a titration setup is shown below. If the burette contains 0.1 M NaOH and the flask contains 20 mL of 0.1 M HCl, what is the pH of the solution after 10 mL of NaOH has been added?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 25
A 0.1 M solution of HCl is titrated with 0.1 M NaOH. If 20 mL of NaOH is added, what is the pH of the solution?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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