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POST UTME BELLS UNIVERSITY 2019 Chemistry | Objective

Are you preparing for POST UTME BELLS UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2019 Chemistry (Objective) questions designed to simulate the real exam environment.

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Question 1

Determine the major product of the reaction between 2-methyl-2-propanol and HCl.

Correct A. 2-chloro-2-methylpropane

B. 2-chloro-2-methyl-1-propanol

C. 2-methyl-2-propanol

D. 2-methyl-1-propanol

Correct Answer: A

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Question 2

Calculate the molar solubility of AgCl in a 0.1 M solution of NaCl.

Correct A. 0.01

B. 0.1

C. 0.5

D. 1

Correct Answer: A

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Question 3

Determine the rate cons\tant (k) for the reaction 2NO + O2 → 2NO2, given that the initial concentration of NO is 0.1 M and the concentration of NO2 is 0.05 M after 10 minutes.

A. 0.05

Correct B. 0.1

C. 0.5

D. 1

Correct Answer: B

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Question 4

A diagram of a titration setup is shown below. If 25.0 mL of 0.1 M NaOH is required to neutralize 20.0 mL of HCl, what is the concentration of HCl?

A. 0.05

Correct B. 0.1

C. 0.5

D. 1

Correct Answer: B

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Question 5

Calculate the pH of a solution containing 0.1 M HCl and 0.1 M NaOH.

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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Question 6

The reaction between sodium thiosulfate and iodine is a first-order reaction. If the initial concentration of sodium thiosulfate is 0.1 M and the rate cons\tant is 0.05 min^-1, calculate the concentration of sodium thiosulfate 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 7

A 2.5 L flask contains 0.5 mol of an ideal gas at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.

A. 1.01 x 10^5 Pa

Correct B. 2.02 x 10^5 Pa

C. 3.03 x 10^5 Pa

D. 4.04 x 10^5 Pa

Correct Answer: B

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Question 8

A solution contains 0.2 M NaCl and 0.1 M CaCl_2. Calculate the concentration of Cl^- ions.

A. 0.3 M

Correct B. 0.4 M

C. 0.5 M

D. 0.6 M

Correct Answer: B

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Question 9

A sample of a metal has a mass of 25 g and a volume of 5 cm^3. Calculate the density of the metal.

A. 5 g/cm^3

Correct B. 10 g/cm^3

C. 15 g/cm^3

D. 20 g/cm^3

Correct Answer: B

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Question 10

A diagram of a titration setup is shown below.

A. The burette contains the acid.

Correct B. The beaker contains the acid.

C. The test tube contains the acid.

D. The burette contains the base.

Correct Answer: B

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Question 11

The reaction between nitrogen dioxide and water is an example of a redox reaction. Write the balanced chemical equation for this reaction, including the oxidation states of the nitrogen atom in the reac\tants and products.

A. \text{NO}_2 + \text{H}_2\text{O} \rightarrow \text{HNO}_3 + \text{H}_2\text{O}

Correct B. \text{NO}_2 + \text{H}_2\text{O} \rightarrow \text{HNO}_3 + \text{NO}

C. \text{NO}_2 + \text{H}_2\text{O} \rightarrow \text{HNO}_3 + \text{H}_2\text{O}_2

D. \text{NO}_2 + \text{H}_2\text{O} \rightarrow \text{HNO}_3 + \text{NO}_2

Correct Answer: B

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Question 12

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

A. 0.05 \text{ M}

B. 0.01 \text{ M}

Correct C. 0.005 \text{ M}

D. 0.0025 \text{ M}

Correct Answer: C

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Question 13

A 2.5 g sample of a metal is dissolved in 50 mL of 0.1 M HCl. If the reaction is complete, what is the number of moles of the metal that reacted?

Correct A. 0.05 \text{ mol}

B. 0.025 \text{ mol}

C. 0.0125 \text{ mol}

D. 0.00625 \text{ mol}

Correct Answer: A

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Question 14

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

Correct A. -110.5 \text{ kJ/mol}

B. -110.5 \text{ kJ/mol}

C. -110.5 \text{ kJ/mol}

D. -110.5 \text{ kJ/mol}

Correct Answer: A

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Question 15

The reaction between sodium and chlorine is an example of a \single displacement reaction. Write the balanced chemical equation for this reaction, including the oxidation states of the sodium and chlorine atoms in the reac\tants and products.

Correct A. \text{Na} + \text{Cl}_2 \rightarrow \text{NaCl}

B. \text{Na} + \text{Cl}_2 \rightarrow \text{Na}_2\text{Cl}_2

C. \text{Na} + \text{Cl}_2 \rightarrow \text{NaCl}_2

D. \text{Na} + \text{Cl}_2 \rightarrow \text{Na}_2\text{Cl}_3

Correct Answer: A

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Question 16

The atomic radius of an element is 100 pm. If the element is in the 4th period, what is the expected value of its atomic radius in the 5th period?

A. 120 pm

B. 150 pm

Correct C. 180 pm

D. 200 pm

Correct Answer: C

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Question 17

A polymer is formed by the condensation reaction of two monomers, A and B. If the molecular weight of the polymer is 500 g/mol, and the molecular weights of A and B are 150 g/mol and 200 g/mol, respectively, what is the ratio of the number of moles of A to the number of moles of B?

A. 1:1

Correct B. 1:2

C. 2:1

D. 3:1

Correct Answer: B

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Question 18

The reaction of an alkane with chlorine gas produces a dichloroalkane. If the alkane has the molecular formula C4H10, what is the structure of the dichloroalkane?

Correct A. CH3CH2CH2CH2Cl2

B. CH3CH2CHClCH3

C. CH3CH2ClCH2CH3

D. CH3ClCH2CH2CH3

Correct Answer: A

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Question 19

A metal oxide has the formula M2O3. If the metal has an atomic number of 24, what is the charge on the metal ion?

Correct A. +3

B. +2

C. +1

D. +4

Correct Answer: A

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Question 20

A solution of a weak acid (HA) has a pH of 3. If the concentration of the acid is 0.1 M, what is the concentration of the hydrogen ions?

Correct A. 0.01 M

B. 0.1 M

C. 1 M

D. 10 M

Correct Answer: A

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Question 21

The solubility of a subs\tance in water is 0.5 g/100 mL at 25°C. If 10 g of the subs\tance is added to 100 mL of water at 25°C, what is the maximum amount of the subs\tance that can dissolve?

A. 2 g

Correct B. 5 g

C. 10 g

D. 15 g

Correct Answer: B

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Question 22

A 2.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 1.0 L of water. What is the pH of the solution?

A. 12

B. 13

Correct C. 14

D. 15

Correct Answer: C

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Question 23

A sample of a polymer has a molecular weight of 100,000 g/mol. If 1.0 g of the polymer is dissolved in 100 mL of solvent, what is the concentration of the solution in g/L?

A. 0.1 g/L

Correct B. 1.0 g/L

C. 10 g/L

D. 100 g/L

Correct Answer: B

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Question 24

A 1.0 M solution of HCl is prepared by dissolving 36.5 g of HCl in 1.0 L of water. What is the pH of the solution?

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

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Question 25

A sample of a non-metal has a mass of 10 g. If the density of the non-metal is 2.5 g/cm^3, what is the volume of the non-metal?

A. 4 cm^3

B. 8 cm^3

Correct C. 12 cm^3

D. 16 cm^3

Correct Answer: C

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