Practice Post UTME LEAD CITY UNIVERSITY chemistry 2023 Past Questions

Question 1

The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.5 mol of C(s) to form CO2(g).

Correct A. -588.25 kJ

B. -588.75 kJ

C. -589.25 kJ

D. -589.75 kJ

Correct Answer: A

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Question 2

The diagram below shows a titration setup.

A. The burette contains the acid.

B. The beaker contains the acid.

Correct C. The burette contains the base.

D. The beaker contains the base.

Correct Answer: C

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Question 3

The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of vaporization of 1 mol of H2O(l) to form H2O(g).

Correct A. -44.0 kJ

B. -44.5 kJ

C. -45.0 kJ

D. -45.5 kJ

Correct Answer: A

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Question 4

The diagram below shows a simple black and white chemistry apparatus showing titration setup.

A. The burette contains the acid.

B. The beaker contains the acid.

Correct C. The burette contains the base.

D. The beaker contains the base.

Correct Answer: C

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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 combustion of 1.5 mol of C(s) to form CO(g).

Correct A. -165.75 kJ

B. -166.25 kJ

C. -166.75 kJ

D. -167.25 kJ

Correct Answer: A

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Question 6

Determine the molar mass of a polymer with the following monomer units: CH2=CH-CH3, CH2=CH-CH2-CH3, and CH2=CH-CH2-CH2-CH3. Assume that the polymer is composed of 50% of each monomer unit.

A. 150 g/mol

Correct B. 200 g/mol

C. 250 g/mol

D. 300 g/mol

Correct Answer: B

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Question 7

A metal alloy is composed of 75% copper and 25% zinc. If the density of copper is 8.96 g/cm^3 and the density of zinc is 7.14 g/cm^3, what is the density of the alloy?

A. 7.5 g/cm^3

B. 8.0 g/cm^3

Correct C. 8.5 g/cm^3

D. 9.0 g/cm^3

Correct Answer: C

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Question 8

A solution of 0.1 M NaOH is mixed with a solution of 0.1 M HCl. What is the pH of the resulting solution?

A. 1

B. 2

Correct C. 7

D. 14

Correct Answer: C

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Question 9

A sample of 1.0 g of a metal is dissolved in 1.0 L of 1.0 M HCl. If the metal has a molar mass of 100 g/mol, what is the concentration of the metal ion in the solution?

A. 0.01 M

B. 0.1 M

Correct C. 1.0 M

D. 10 M

Correct Answer: C

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Question 10

A diagram of a titration setup is shown below. The burette contains 0.1 M NaOH, and the flask contains 25 mL of 0.1 M HCl. What is the pH of the resulting solution after the titration?

A. 1

B. 2

Correct C. 7

D. 14

Correct Answer: C

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Question 11

A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If 20 mL of the acid solution requires 15 mL of NaOH for neutralization, calculate the number of moles of HA in 1 L of the acid solution.

A. 0.01 mol

Correct B. 0.02 mol

C. 0.03 mol

D. 0.04 mol

Correct Answer: B

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Question 12

A solution containing 0.1 M NaCl is electrolyzed u\sing a current of 0.5 A for 2 hours. Calculate the mass of Cl2 gas produced at the anode.

A. 0.1 g

B. 0.2 g

Correct C. 0.3 g

D. 0.4 g

Correct Answer: C

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Question 13

A 2 M solution of H2SO4 is mixed with 1 M NaOH. Calculate the pH of the resulting solution.

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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Question 14

A 0.1 M solution of a weak base B is titrated with 0.1 M HCl. If 20 mL of the base solution requires 15 mL of HCl for neutralization, calculate the number of moles of B in 1 L of the base solution.

A. 0.01 mol

Correct B. 0.02 mol

C. 0.03 mol

D. 0.04 mol

Correct Answer: B

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Question 15

A solution containing 0.1 M NaOH is electrolyzed u\sing a current of 0.5 A for 2 hours. Calculate the mass of O2 gas produced at the cathode.

A. 0.1 g

B. 0.2 g

Correct C. 0.3 g

D. 0.4 g

Correct Answer: C

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Question 16

A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. If 25 mL of the acid is titrated with 15 mL of the base, what is the pH of the resulting solution?

A. 3

B. 4

Correct C. 5

D. 6

Correct Answer: C

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Question 17

A sample of a gas at 25°C and 1 atm is collected over water at 25°C. If the partial pressure of the gas is 0.8 atm, what is the mole \fraction of the gas?

A. 0.4

Correct B. 0.5

C. 0.6

D. 0.7

Correct Answer: B

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Question 18

A solution of NaOH is prepared by dissolving 10 g of NaOH in 100 g of water. What is the molarity of the solution?

A. 0.1 M

Correct B. 0.5 M

C. 1 M

D. 2 M

Correct Answer: B

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Question 19

A 2.0 L flask contains 0.5 mol of CO2 at 25°C. If 1.0 mol of O2 is added to the flask, what is the total pressure of the gas mixture?

A. 2 atm

B. 3 atm

Correct C. 4 atm

D. 5 atm

Correct Answer: C

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Question 20

A 0.1 M solution of a weak acid is titrated with 0.1 M NaOH. If 20 mL of the acid is titrated with 10 mL of the base, what is the pH of the resulting solution?

A. 2

B. 3

C. 4

Correct D. 5

Correct Answer: D

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Question 21

Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K, given that the rate cons\tant at 298 K is 1.5 × 10^\( -2 \) s^\( -1 \) and the activation energy (Ea) is 2.5 × 10^5 J/mol.

A. 1.2 × 10^\( -2 \) s^\( -1 \)

Correct B. 1.5 × 10^\( -2 \) s^\( -1 \)

C. 1.8 × 10^\( -2 \) s^\( -1 \)

D. 2.0 × 10^\( -2 \) s^\( -1 \)

Correct Answer: B

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Question 22

A 2.5 M solution of H2SO4 is prepared by dissolving 2.5 g of H2SO4 in 100 mL of water. What is the molarity of the solution?

A. 2.0 M

Correct B. 2.5 M

C. 3.0 M

D. 3.5 M

Correct Answer: B

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Question 23

The reaction: 2NO(g) + O2(g) → 2NO2(g) has a rate cons\tant (k) of 1.5 × 10^\( -2 \) s^\( -1 \) at 298 K. If the activation energy (Ea) is 2.5 × 10^5 J/mol, what is the rate cons\tant (k) at 308 K?

A. 2.0 × 10^\( -2 \) s^\( -1 \)

Correct B. 2.5 × 10^\( -2 \) s^\( -1 \)

C. 3.0 × 10^\( -2 \) s^\( -1 \)

D. 3.5 × 10^\( -2 \) s^\( -1 \)

Correct Answer: B

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Question 24

A 2.5 M solution of H2SO4 is prepared by dissolving 2.5 g of H2SO4 in 100 mL of water. What is the mass of H2SO4 required to prepare a 1.0 M solution?

Correct A. 1.0 g

B. 1.5 g

C. 2.0 g

D. 2.5 g

Correct Answer: A

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Question 25

The reaction: 2NO(g) + O2(g) → 2NO2(g) has a rate cons\tant (k) of 1.5 × 10^\( -2 \) s^\( -1 \) at 298 K. If the activation energy (Ea) is 2.5 × 10^5 J/mol, what is the rate cons\tant (k) at 308 K?

A. 2.0 × 10^\( -2 \) s^\( -1 \)

Correct B. 2.5 × 10^\( -2 \) s^\( -1 \)

C. 3.0 × 10^\( -2 \) s^\( -1 \)

D. 3.5 × 10^\( -2 \) s^\( -1 \)

Correct Answer: B

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