POST UTME UNN 2018 Chemistry | Objective

Are you preparing for POST UTME UNN exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2018 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1
Determine the number of unpaired electrons in the ground state of a neutral chromium atom.
A. 0
Correct B. 2
C. 4
D. 6

Correct Answer: B

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Question 2
A 0.5 M solution of NaCl is prepared by dissolving 25 g of NaCl in 1000 mL of water. What is the concentration of the solution in g/L?
Correct A. 0.25 g/L
B. 0.5 g/L
C. 1.0 g/L
D. 2.0 g/L

Correct Answer: A

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Question 3
A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
Correct A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M

Correct Answer: A

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Question 4
A gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 300 K. What is the new volume of the gas if the pressure is increased to 3.0 atm and the temperature is decreased to 200 K?
A. 1.0 L
B. 1.5 L
Correct C. 2.0 L
D. 2.5 L

Correct Answer: C

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Question 5
A diagram of a chromatography setup is shown below. If the retention time of a particular compound is 15 minutes, what is the concentration of the compound in the sample?
A. 0.1 mg/mL
B. 0.5 mg/mL
Correct C. 1.0 mg/mL
D. 5.0 mg/mL

Correct Answer: C

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Question 6
The reaction of nitrogen with oxygen to form nitrogen dioxide is represented by the equation: 4NO + O2 → 2N2O4. What is the oxidation state of nitrogen in N2O4?
A. +2
Correct B. +4
C. +6
D. +8

Correct Answer: B

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Question 7
A sample of oxygen gas occupies a volume of 2.5 liters at a pressure of 1 atm and a temperature of 298 K. What is the number of moles of oxygen gas present?
A. 0.010
Correct B. 0.0224
C. 0.0348
D. 0.0472

Correct Answer: B

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Question 8
The diagram below shows a titration setup. What is the purpose of the burette?
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 9
The graph below shows the relationship between the volume of a gas and its pressure. What is the slope of the graph?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 10
The reaction of sodium with water is represented by the equation: 2Na + 2H2O → 2NaOH + H2. What is the oxidation state of sodium in NaOH?
Correct A. +1
B. +2
C. +3
D. +4

Correct Answer: A

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Question 11
The reaction of sodium with water is highly exothermic. What is the primary product of this reaction?
Correct A. Sodium hydroxide (NaOH)
B. Sodium carbonate (Na2CO3)
C. Sodium chloride (NaCl)
D. Sodium oxide (Na2O)

Correct Answer: A

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Question 12
A sample of a polymer has a molecular weight of 100,000 g/mol. If 2.5 g of the polymer is dissolved in 50 mL of solvent, what is the concentration of the solution in g/L?
A. 0.05 g/L
Correct B. 0.5 g/L
C. 5 g/L
D. 50 g/L

Correct Answer: B

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Question 13
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, how much will remain after 10 years?
A. 50 g
B. 25 g
Correct C. 12.5 g
D. 6.25 g

Correct Answer: C

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Question 14
A solution of 0.1 M HCl is mixed with a solution of 0.1 M NaOH. What is the pH of the resulting solution?
A. 1
Correct B. 7
C. 10
D. 14

Correct Answer: B

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Question 15
A metal M reacts with oxygen to form a basic oxide. The reaction is as follows: 4M + 3O2 → 2M2O3. What is the oxidation state of M in the product?
Correct A. +3
B. +2
C. +1
D. -2

Correct Answer: A

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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 metal (X) reacts with dilute hydrochloric acid to produce a gas (Y). The gas (Y) is used in the manufacture of semiconductors. Identify the metal (X) and the gas (Y).
Correct A. Zinc, Hydrogen
B. Iron, Carbon Dioxide
C. Copper, Oxygen
D. Lead, Nitrogen

Correct Answer: A

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Question 18
The diagram below shows a titration setup. Identify the subs\tance being titrated.
A. Acid
Correct B. Base
C. Salt
D. Water

Correct Answer: B

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Question 19
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the concentration of the resulting solution after the reaction is complete?
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 20
The diagram below shows a circuit. Identify the component labeled A.
Correct A. Resistor
B. Battery
C. Capacitor
D. Inductor

Correct Answer: A

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Question 21
A 2.00 M solution of NaOH is mixed with a 1.00 M solution of HCl. What is the resulting concentration of the solution after the reaction is complete?
A. 1.00 M
Correct B. 1.50 M
C. 2.00 M
D. 3.00 M

Correct Answer: B

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Question 22
A 100.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the reaction is complete?
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 23
A 2.00 M solution of NaOH is mixed with a 1.00 M solution of HCl. What is the resulting concentration of the solution after the reaction is complete?
A. 1.00 M
Correct B. 1.50 M
C. 2.00 M
D. 3.00 M

Correct Answer: B

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Question 24
A 100.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the reaction is complete?
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 25
A 2.00 M solution of NaOH is mixed with a 1.00 M solution of HCl. What is the resulting concentration of the solution after the reaction is complete?
A. 1.00 M
Correct B. 1.50 M
C. 2.00 M
D. 3.00 M

Correct Answer: B

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