POST UTME KSU 2020 Chemistry | Objective

Are you preparing for POST UTME KSU 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
The energy change associated with the formation of a mole of a solid from its gaseous reac\tants is typically
A. exothermic
B. \endothermic
Correct C. neither exothermic nor \endothermic
D. dep\endent on the specific reaction

Correct Answer: C

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Question 2
A solution of 0.1 M NaCl is prepared by dissolving 6.0 g of NaCl in 1000 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. 0.5 M

Correct Answer: B

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Question 3
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 measure the pH of the solution

Correct Answer: A

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Question 4
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
Correct B. -241.8 kJ/mol
C. -393.5 kJ/mol
D. -572.8 kJ/mol

Correct Answer: B

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Question 5
A 0.1 M solution of NaOH is prepared by dissolving 4.0 g of NaOH in 1000 mL of water. What is the pH of the solution?
A. 13
Correct B. 14
C. 15
D. 16

Correct Answer: B

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Question 6
A sample of a gas at 25°C and 1 atm is heated to 50°C at cons\tant volume. What is the new pressure of the gas, assuming ideal gas behavior?
A. 1.5 atm
Correct B. 2 atm
C. 3 atm
D. 4 atm

Correct Answer: B

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Question 7
A 2.5 M solution of NaOH is titrated with 0.5 M HCl. What is the pH of the solution after 25 mL of HCl has been added?
A. 9
B. 10
Correct C. 11
D. 12

Correct Answer: C

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Question 8
A mixture of 2.0 g of NaCl and 3.0 g of KNO3 is dissolved in 100 mL of water. What is the molarity of 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 9
A 1.0 L flask contains 0.5 mol of CO2 at 25°C. What is the partial pressure of CO2 in the flask?
A. 0.5 atm
Correct B. 1 atm
C. 1.5 atm
D. 2 atm

Correct Answer: B

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Question 10
A 2.0 M solution of HCl is titrated with 1.0 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 7
B. 8
Correct C. 9
D. 10

Correct Answer: C

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Question 11
The atomic radius of an element decreases across a period in the periodic table. Which of the following is a correct explanation for this tr\end?
Correct A. The effective nuclear charge increases across a period.
B. The atomic radius increases across a period.
C. The number of electrons in the outermost energy level increases across a period.
D. The atomic radius remains cons\tant across a period.

Correct Answer: A

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Question 12
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 1
B. 2
Correct C. 3
D. 4

Correct Answer: C

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Question 13
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 14
A sample of air is collected over water and found to have a partial pressure of 0.1 atm. What is the mole \fraction of the gas in the air?
A. 0.1
Correct B. 0.2
C. 0.3
D. 0.4

Correct Answer: B

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Question 15
The diagram below shows a circuit setup. What is the purpose of the resistor?
Correct A. To reduce the voltage across the circuit.
B. To increase the current through the circuit.
C. To decrease the current through the circuit.
D. To measure the voltage across the circuit.

Correct Answer: A

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Question 16
The reaction between nitrogen dioxide (NO2) and water (H2O) produces nitric acid (HNO3) and nitric oxide (NO). The balanced chemical equation for this reaction is: 3NO2 + H2O → 2HNO3 + NO. If 2.5 moles of NO2 react with excess water, what is the limiting reac\tant?
Correct A. NO2
B. H2O
C. HNO3
D. NO

Correct Answer: A

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Question 17
A 2.5 M solution of hydrochloric acid (HCl) is mixed with a 1.5 M solution of sodium hydroxide (NaOH). What is the concentration of the resulting solution?
A. 1.0 M
Correct B. 2.0 M
C. 3.0 M
D. 4.0 M

Correct Answer: B

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Question 18
The compound benzene (C6H6) is a hydrocarbon with the molecular formula C6H6. What is the IUPAC name of this compound?
Correct A. Benzene
B. Toluene
C. Xylene
D. Ethylbenzene

Correct Answer: A

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Question 19
The reaction between sulfuric acid (H2SO4) and sodium hydroxide (NaOH) produces sodium sulfate (Na2SO4) and water (H2O). The balanced chemical equation for this reaction is: H2SO4 + 2NaOH → Na2SO4 + 2H2O. If 2.0 moles of H2SO4 react with excess NaOH, what is the limiting reac\tant?
Correct A. H2SO4
B. NaOH
C. Na2SO4
D. H2O

Correct Answer: A

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Question 20
A 1.0 M solution of hydrochloric acid (HCl) is mixed with a 2.0 M solution of sodium hydroxide (NaOH). What is the concentration of the resulting solution?
A. 0.5 M
B. 1.0 M
Correct C. 1.5 M
D. 2.0 M

Correct Answer: C

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Question 21
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after 25.0 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 22
A metal (M) reacts with chlorine gas to form a white solid. The reaction is as follows: M + Cl2 → MCl2. If 2.50 g of MCl2 is formed from 1.50 g of M, what is the molar mass of M?
A. 50.0 g/mol
Correct B. 75.0 g/mol
C. 100 g/mol
D. 150 g/mol

Correct Answer: B

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Question 23
A 2.00 M solution of H2SO4 is titrated with 1.00 M NaOH. What is the pH of the solution after 20.0 mL of NaOH has been added?
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 24
A metal (M) reacts with oxygen gas to form a white solid. The reaction is as follows: 4M + 3O2 → 2M2O3. If 2.50 g of M2O3 is formed from 1.50 g of M, what is the molar mass of M?
A. 50.0 g/mol
B. 75.0 g/mol
Correct C. 100 g/mol
D. 150 g/mol

Correct Answer: C

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Question 25
A 1.00 M solution of HCl is titrated with 1.00 M NaOH. What is the pH of the solution after 10.0 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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