POST UTME COAL CITY UNIVERSITY 2021 Chemistry | Objective

Are you preparing for POST UTME COAL CITY UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2021 Chemistry (Objective) questions designed to simulate the real exam environment.

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Question 1
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. -1206.5 kJ/mol
B. -1206.5 kJ/mol
C. -1206.5 kJ/mol
D. -1206.5 kJ/mol

Correct Answer: A

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Question 2
A 2.5 M solution of HCl is mixed with a 1.0 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
Correct A. 2.5
B. 2.5
C. 2.5
D. 2.5

Correct Answer: A

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Question 3
The s\tandard enthalpy of formation of NH3(g) is -45.9 kJ/mol. Calculate the s\tandard enthalpy of formation of N2H4(l) u\sing the following reaction: N2(g) + 3H2(g) → N2H4(l).
Correct A. -50.6 kJ/mol
B. -50.6 kJ/mol
C. -50.6 kJ/mol
D. -50.6 kJ/mol

Correct Answer: A

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Question 4
A 1.0 M solution of H2SO4 is mixed with a 2.0 M solution of Ba(OH)2. Calculate the pH of the resulting solution after the reaction is complete.
Correct A. 2
B. 2
C. 2
D. 2

Correct Answer: A

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Question 5
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CH4(g) u\sing the following reaction: C(s) + 2H2(g) → CH4(g).
Correct A. -74.8 kJ/mol
B. -74.8 kJ/mol
C. -74.8 kJ/mol
D. -74.8 kJ/mol

Correct Answer: A

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Question 6
A 0.5 M solution of potassium permanganate (KMnO4) is electrolyzed u\sing a platinum electrode. If the cell potential is 1.5 V, calculate the number of moles of oxygen gas evolved at the anode.
A. 0.06 mol
B. 0.12 mol
Correct C. 0.18 mol
D. 0.24 mol

Correct Answer: C

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Question 7
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. If the concentration of the solution is 0.5 g/mL, calculate the molar mass of the polymer.
A. 500 g/mol
Correct B. 1000 g/mol
C. 1500 g/mol
D. 2000 g/mol

Correct Answer: B

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Question 8
A 0.1 M solution of sodium hydroxide (NaOH) is mixed with a 0.2 M solution of hydrochloric acid (HCl). If the reaction is allowed to proceed to completion, calculate the concentration of the resulting solution.
A. 0.05 M
Correct B. 0.15 M
C. 0.25 M
D. 0.35 M

Correct Answer: B

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Question 9
A 1.5 g sample of a solid is dissolved in 100 mL of a solvent. If the concentration of the solution is 0.05 g/mL, calculate the molar mass of the solid.
A. 200 g/mol
B. 400 g/mol
Correct C. 600 g/mol
D. 800 g/mol

Correct Answer: C

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Question 10
A 0.5 M solution of potassium chloride (KCl) is electrolyzed u\sing a platinum electrode. If the cell potential is 2.5 V, calculate the number of moles of chlorine gas evolved at the anode.
A. 0.08 mol
B. 0.16 mol
Correct C. 0.24 mol
D. 0.32 mol

Correct Answer: C

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Question 11
Determine the pH of a 0.1 M solution of HCl at 25°C, given that the dissociation cons\tant of HCl is 10^\( -7 \).
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 12
A 25.0 mL sample of 0.1 M NaOH is titrated with 0.1 M HCl. Calculate the pH of the solution after the addition of 15.0 mL of HCl.
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

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Question 13
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the repeating unit.
A. 100
B. 200
Correct C. 300
D. 400

Correct Answer: C

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Question 14
A 1.0 L solution of 0.1 M NaOH is mixed with 1.0 L of 0.1 M HCl. Calculate the pH of the resulting solution.
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 15
A 25.0 mL sample of 0.1 M NaOH is titrated with 0.1 M HCl. Calculate the number of moles of HCl added at the equivalence point.
A. 0.01
Correct B. 0.02
C. 0.03
D. 0.04

Correct Answer: B

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Question 16
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. If 20 mL of the acid solution is titrated with 25 mL of the base solution, what is the pH of the resulting solution?
A. 3.5
Correct B. 4.5
C. 5.5
D. 6.5

Correct Answer: B

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Question 17
A sample of a metal oxide is heated in a crucible. The mass of the oxide is 25.0 g, and the mass of the metal obtained is 15.0 g. What is the percentage yield of the metal?
A. 40%
B. 50%
Correct C. 60%
D. 70%

Correct Answer: C

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Question 18
A solution of a weak acid (HA) is 0.1 M. If 10 mL of this solution is titrated with 0.1 M NaOH, what is the pH of the resulting solution?
A. 3.5
B. 4.5
Correct C. 5.5
D. 6.5

Correct Answer: C

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Question 19
A sample of a metal hydroxide is dissolved in water to form a solution. The concentration of the solution is 0.1 M. If 20 mL of this solution is titrated with 0.1 M HCl, what is the pH of the resulting solution?
A. 3.5
B. 4.5
C. 5.5
Correct D. 6.5

Correct Answer: D

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Question 20
A solution of a weak base (BOH) is 0.1 M. If 10 mL of this solution is titrated with 0.1 M HCl, what is the pH of the resulting solution?
A. 3.5
Correct B. 4.5
C. 5.5
D. 6.5

Correct Answer: B

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Question 21
In a study on the environmental impact of industrial activities, a researcher measured the concentration of heavy metals in soil samples. The data showed a significant increase in metal concentrations near industrial sites. Which of the following is a likely consequence of this finding?
Correct A. Increased risk of cancer in humans
B. Decreased fertility in plants
C. Accelerated soil erosion
D. Enhanced soil nutrient cycling

Correct Answer: A

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Question 22
A sample of a metal alloy contains 85% copper, 10% zinc, and 5% tin. If 250 g of the alloy is melted and cast into a new shape, what is the mass of copper in the new shape?
Correct A. 187.5 g
B. 200 g
C. 212.5 g
D. 225 g

Correct Answer: A

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Question 23
A polymer is composed of repeating units of the following structure: CH2-CH2-CH2-CH2. What is the name of this polymer?
Correct A. Polyethylene
B. Polypropylene
C. Polyvinyl chloride
D. Polystyrene

Correct Answer: A

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Question 24
A solution of sodium hydroxide (NaOH) is prepared by dissolving 25 g of NaOH in 100 mL of water. What is the molarity of the solution?
Correct A. 0.625 M
B. 0.75 M
C. 1.25 M
D. 1.5 M

Correct Answer: A

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Question 25
A metal ore is composed of 80% iron(II) oxide (FeO) and 20% silica (SiO2). If 500 g of the ore is heated in a furnace, what is the mass of iron produced?
Correct A. 400 g
B. 420 g
C. 440 g
D. 460 g

Correct Answer: A

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