POST UTME WELLSPRING UNIVERSITY 2018 Chemistry | Objective

Are you preparing for POST UTME WELLSPRING UNIVERSITY 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.

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Question 1
Determine the number of moles of oxygen gas (O2) produced at STP when 2.5 moles of hydrogen gas (H2) react with excess oxygen gas according to the equation: 2H2 + O2 → 2H2O.
Correct A. 1.25 moles
B. 2.5 moles
C. 5 moles
D. 10 moles

Correct Answer: A

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Question 2
A 2.5 M solution of sodium hydroxide (NaOH) is titrated with a 0.5 M solution of hydrochloric acid (HCl). What is the pH of the resulting solution after 25 mL of HCl has been added?
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 3
The diagram below shows a titration setup. Identify the part labeled A.
Correct A. Burette
B. Beaker
C. Test tube
D. Cylinder

Correct Answer: A

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Question 4
A 1.0 M solution of acetic acid (CH3COOH) is mixed with a 1.0 M solution of sodium hydroxide (NaOH). 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 5
The diagram below shows a simple black and white chemistry apparatus showing a titration setup. Identify the part labeled A.
Correct A. Burette
B. Beaker
C. Test tube
D. Cylinder

Correct Answer: A

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Question 6
Determine the number of moles of glu\cose (C6H12O6) that can be obtained from 2.5 moles of ethene (C2H4) if the reaction is: C2H4 + 3O2 → C2H4O2 + 2CO2 + 3H2O. The balanced equation for the combustion of glu\cose is: C6H12O6 + 6O2 → 6CO2 + 6H2O.
Correct A. 1.5 moles
B. 2.5 moles
C. 3.0 moles
D. 4.0 moles

Correct Answer: A

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Question 7
A sample of 0.500 g of a polymer is dissolved in 100.0 mL of a solvent. If the density of the solution is 1.05 g/mL, what is the molar mass of the polymer?
A. 500 g/mol
B. 1000 g/mol
Correct C. 2000 g/mol
D. 5000 g/mol

Correct Answer: C

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Question 8
The half-life of a radioactive subs\tance is 5.0 days. If a sample initially contains 1000 mg of the subs\tance, what is the mass remaining after 20 days?
Correct A. 100 mg
B. 200 mg
C. 500 mg
D. 1000 mg

Correct Answer: A

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Question 9
A 2.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. What is the pH of the resulting solution?
A. 1.0
Correct B. 2.0
C. 3.0
D. 4.0

Correct Answer: B

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Question 10
A 1.0 M solution of H2SO4 is mixed with a 2.0 M solution of NaOH. What is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
Correct D. 4.0

Correct Answer: D

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Question 11
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. - 180.5 kJ/mol
B. - 393.5 kJ/mol
Correct C. - 180.5 kJ/mol + 393.5 kJ/mol
D. - 393.5 kJ/mol - 180.5 kJ/mol

Correct Answer: C

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Question 12
A 2.50 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
A. 2.00
Correct B. 2.50
C. 3.00
D. 3.50

Correct Answer: B

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Question 13
The s\tandard enthalpy of combustion of glu\cose (C6H12O6) is -2802 kJ/mol. Calculate the s\tandard enthalpy of formation of glu\cose.
A. - 2802 kJ/mol
Correct B. - 2802 kJ/mol + 6 \cdot 393.5 kJ/mol
C. - 2802 kJ/mol - 6 \cdot 393.5 kJ/mol
D. - 393.5 kJ/mol

Correct Answer: B

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Question 14
A 0.100 M solution of HCl is mixed with a 0.100 M solution of NaOH. Calculate the pH of the resulting 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 15
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of combustion of glu\cose (C6H12O6) u\sing the following reaction: C6H12O6(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l).
A. - 2802 kJ/mol
Correct B. - 285.8 kJ/mol + 6 \cdot 393.5 kJ/mol
C. - 285.8 kJ/mol - 6 \cdot 393.5 kJ/mol
D. - 393.5 kJ/mol

Correct Answer: B

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Question 16
A 1.00 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting 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 17
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. - 180.5 kJ/mol
B. - 393.5 kJ/mol
Correct C. - 180.5 kJ/mol + 393.5 kJ/mol
D. - 393.5 kJ/mol - 180.5 kJ/mol

Correct Answer: C

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Question 18
A 0.100 M solution of HCl is mixed with a 0.100 M solution of NaOH. Calculate the pH of the resulting 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 19
In the electrolysis of a molten ionic compound, what is the primary function of the inert electrode?
Correct A. To facilitate the flow of ions towards the electrode
B. To prevent the reaction from occurring
C. To provide a path for the electrons to flow
D. To increase the temperature of the electrolyte

Correct Answer: A

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Question 20
A sample of a non-metallic element has a mass of 25.0 g and a volume of 10.0 cm³. What is the density of the element?
Correct A. 2.5 g/cm³
B. 2.0 g/cm³
C. 1.5 g/cm³
D. 1.0 g/cm³

Correct Answer: A

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Question 21
A solution contains 0.100 M NaCl. What is the concentration of Cl⁻ ions in the solution?
A. 0.050 M
Correct B. 0.100 M
C. 0.200 M
D. 0.500 M

Correct Answer: B

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Question 22
A sample of a metal has a mass of 50.0 g and a volume of 5.0 cm³. What is the density of the metal?
Correct A. 10.0 g/cm³
B. 5.0 g/cm³
C. 2.5 g/cm³
D. 1.0 g/cm³

Correct Answer: A

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Question 23
A solution contains 0.050 M HCl. What is the concentration of H⁺ ions in the solution?
A. 0.025 M
Correct B. 0.050 M
C. 0.100 M
D. 0.200 M

Correct Answer: B

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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 formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
Correct A. -1781.5 kJ/mol
B. -1781.5 kJ/mol
C. -1781.5 kJ/mol
D. -1781.5 kJ/mol

Correct Answer: A

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Question 25
A 2.50 g sample of a metal is heated in a crucible until it is completely oxidized. The mass of the crucible and the oxide formed is 3.25 g. Calculate the percentage of the metal that is oxidized.
Correct A. 80.0%
B. 80.0%
C. 80.0%
D. 80.0%

Correct Answer: A

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