Practice Post UTME SUMMIT UNIVERSITY chemistry 2023 Past Questions

Question 1

Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol, ΔHf(C(s)) = 0 kJ/mol.

Correct A. -1206.60 kJ/mol

B. -1206.61 kJ/mol

C. -1206.59 kJ/mol

D. -1206.62 kJ/mol

Correct Answer: A

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Question 2

A diagram of a metal alloy is shown below. What is the primary function of the alloy in the diagram?

A. To store a chemical reagent

Correct B. To measure the volume of a liquid

C. To mix two chemicals together

D. To filter a solution

Correct Answer: B

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Question 3

The rate cons\tant for a first-order reaction is 0.05 min^-1. If the initial concentration of the reac\tant is 0.1 M, what is the concentration of the reac\tant after 10 minutes?

Correct A. 0.005 M

B. 0.01 M

C. 0.05 M

D. 0.1 M

Correct Answer: A

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Question 4

A diagram of an atomic structure is shown below. What is the primary function of the nucleus in the diagram?

Correct A. To store the protons and neutrons of the atom

B. To orbit around the nucleus

C. To carry a negative charge

D. To carry a positive charge

Correct Answer: A

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Question 5

The molar mass of a compound is 180 g/mol. If 2.5 g of the compound is dissolved in 50 mL of water, what is the concentration of the solution in g/L?

A. 0.1 g/L

B. 0.2 g/L

Correct C. 0.5 g/L

D. 1.0 g/L

Correct Answer: C

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Question 6

A 2.50 g sample of a non-metallic oxide of nitrogen is dissolved in 25.0 cm³ of water. The solution is then titrated with 0.100 M HCl. If 25.0 cm³ of 0.100 M HCl is required to reach the equivalence point, calculate the molar mass of the oxide.

A. 62.0 g/mol

Correct B. 62.5 g/mol

C. 63.0 g/mol

D. 64.0 g/mol

Correct Answer: B

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Question 7

A 0.500 M solution of a weak acid, HA, is titrated with 0.100 M NaOH. If 25.0 cm³ of 0.100 M NaOH is required to reach the equivalence point, calculate the pH of the solution at the equivalence point.

A. 2.00

Correct B. 2.50

C. 3.00

D. 3.50

Correct Answer: B

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Question 8

A 2.00 g sample of a non-metallic oxide of nitrogen is dissolved in 25.0 cm³ of water. The solution is then titrated with 0.100 M HCl. If 25.0 cm³ of 0.100 M HCl is required to reach the equivalence point, calculate the molar mass of the oxide.

A. 62.0 g/mol

Correct B. 62.5 g/mol

C. 63.0 g/mol

D. 64.0 g/mol

Correct Answer: B

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Question 9

A 0.500 M solution of a weak acid, HA, is titrated with 0.100 M NaOH. If 25.0 cm³ of 0.100 M NaOH is required to reach the equivalence point, calculate the pH of the solution at the equivalence point.

A. 2.00

Correct B. 2.50

C. 3.00

D. 3.50

Correct Answer: B

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Question 10

A 2.00 g sample of a non-metallic oxide of nitrogen is dissolved in 25.0 cm³ of water. The solution is then titrated with 0.100 M HCl. If 25.0 cm³ of 0.100 M HCl is required to reach the equivalence point, calculate the molar mass of the oxide.

A. 62.0 g/mol

Correct B. 62.5 g/mol

C. 63.0 g/mol

D. 64.0 g/mol

Correct Answer: B

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Question 11

The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of copper in the product Cu(s)?

A. 0

B. +1

Correct C. +2

D. -1

Correct Answer: C

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Question 12

A 2.5 M solution of sodium hydroxide (NaOH) is prepared by dissolving 2.5 g of NaOH in water to make 250 mL of solution. What is the concentration of the solution in terms of molarity?

A. 0.01 M

B. 0.1 M

Correct C. 1 M

D. 10 M

Correct Answer: C

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Question 13

A 10 mL sample of a solution containing 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 5 mL of NaOH?

A. 1

B. 2

Correct C. 3

D. 4

Correct Answer: C

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Question 14

A gas at 25°C and 1 atm is compressed to 2 atm at cons\tant temperature. What is the final volume of the gas?

A. 1 L

Correct B. 2 L

C. 3 L

D. 4 L

Correct Answer: B

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Question 15

A catalyst is added to a reaction mixture containing 1 M H2 and 1 M O2. The reaction is represented by the equation: 2H2(g) + O2(g) → 2H2O(l). What is the rate of reaction?

A. 0.1 M/s

B. 0.5 M/s

Correct C. 1 M/s

D. 5 M/s

Correct Answer: C

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Question 16

The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100g, how much of the subs\tance will remain after 15 years?

Correct A. 12.5g

B. 25g

C. 50g

D. 100g

Correct Answer: A

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Question 17

A solution of 0.1M HCl is titrated with 0.1M NaOH. If 20ml of NaOH is required to reach the equivalence point, what is the volume of HCl required to reach the equivalence point?

A. 20ml

Correct B. 40ml

C. 60ml

D. 80ml

Correct Answer: B

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Question 18

The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. The s\tandard enthalpy of formation of H2O is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of CH4?

A. -74.8 kJ/mol

B. -74.9 kJ/mol

Correct C. -75.0 kJ/mol

D. -75.1 kJ/mol

Correct Answer: C

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Question 19

A solution of 0.1M HCl is titrated with 0.1M NaOH. If 20ml of NaOH is required to reach the equivalence point, what is the concentration of HCl?

Correct A. 0.1M

B. 0.2M

C. 0.3M

D. 0.4M

Correct Answer: A

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Question 20

The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100g, how much of the subs\tance will remain after 10 years?

A. 50g

B. 75g

Correct C. 87.5g

D. 100g

Correct Answer: C

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Question 21

The rate cons\tant (k) for a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, what is the value of the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^-1?

A. 1.0 x 10^5 s^-1

B. 1.0 x 10^6 s^-1

Correct C. 1.0 x 10^7 s^-1

D. 1.0 x 10^8 s^-1

Correct Answer: C

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Question 22

A 2.5 M solution of HCl is titrated with 0.5 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?

A. 1.0

Correct B. 2.0

C. 3.0

D. 4.0

Correct Answer: B

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Question 23

A metal M has a s\tandard electrode potential (E°) of +0.5 V. What is the s\tandard Gibbs free energy change (ΔG°) for the reaction: M → M^+ + e^-?

Correct A. -0.5 kJ/mol

B. -1.0 kJ/mol

C. -1.5 kJ/mol

D. -2.0 kJ/mol

Correct Answer: A

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Question 24

A 1.0 M solution of NaOH is titrated with 0.5 M HCl. What is the pH of the solution after 50 mL of HCl has been added?

A. 1.0

B. 2.0

C. 3.0

Correct D. 4.0

Correct Answer: D

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Question 25

A metal M has a s\tandard electrode potential (E°) of -0.5 V. What is the s\tandard Gibbs free energy change (ΔG°) for the reaction: M → M^+ + e^-?

A. 0.5 kJ/mol

B. 1.0 kJ/mol

C. 1.5 kJ/mol

Correct D. 2.0 kJ/mol

Correct Answer: D

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