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POST UTME SKYLINE UNIVERSITY 2018 Chemistry | Objective

Are you preparing for POST UTME SKYLINE 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

The reaction 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) is an example of a redox reaction. What is the oxidation state of Al in the reac\tant and product?

A. 0

B. +3

Correct C. -3

D. +1

Correct Answer: C

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Question 2

The diagram below shows the structure of a polymer chain. What is the type of polymer?

Correct A. Thermoplastic

B. Thermosetting

C. Elastomer

D. Fibers

Correct Answer: A

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Question 3

The rate cons\tant (k) of a reaction is related to the activation energy (Ea) by the equation: k = Ae^\( -Ea/RT \). What is the unit of the rate cons\tant (k) in this equation?

A. mol/Ls

B. mol/Ls^2

Correct C. s^\( -1 \)

D. L/mol/s

Correct Answer: C

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Question 4

The reaction 2CH4(g) + 3O2(g) → 2CO2(g) + 4H2O(g) is an example of a combustion reaction. What is the limiting reac\tant if 1.5 mol of CH4 and 2.5 mol of O2 are present?

Correct A. CH4

B. O2

C. Neither

D. Both

Correct Answer: A

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Question 5

The diagram below shows the structure of a biomolecule. What is the type of biomolecule?

Correct A. Protein

B. Carbohydrate

C. Lipid

D. Nucleic Acid

Correct Answer: A

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Question 6

A 0.1 M solution of a monoprotic acid, HA, has a pH of 2.50. What is the concentration of the acid in the solution?

Correct A. 0.01 M

B. 0.1 M

C. 0.5 M

D. 1 M

Correct Answer: A

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Question 7

A sample of a solid salt, MX2, has a molar mass of 200 g/mol. If 2.50 g of the salt is dissolved in 100 mL of water, what is the concentration of the salt in the solution?

A. 0.05 M

Correct B. 0.1 M

C. 0.2 M

D. 0.5 M

Correct Answer: B

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Question 8

A solution contains 0.1 M NaOH and 0.1 M HCl. What is the pH of the solution after the reaction is complete?

A. 0

B. 1

C. 2

Correct D. 7

Correct Answer: D

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Question 9

A 0.1 M solution of a weak acid, HA, has a pH of 3.50. What is the concentration of the acid in the solution?

Correct A. 0.01 M

B. 0.1 M

C. 0.5 M

D. 1 M

Correct Answer: A

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Question 10

A sample of a solid salt, MX2, has a molar mass of 250 g/mol. If 3.75 g of the salt is dissolved in 150 mL of water, what is the concentration of the salt in the solution?

A. 0.1 M

Correct B. 0.2 M

C. 0.3 M

D. 0.5 M

Correct Answer: B

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Question 11

The atomic radius of an element decreases across a period in the periodic table. Which of the following is a possible reason for this tr\end?

A. Increa\sing electronegativity across a period

B. Decrea\sing atomic number across a period

Correct C. Increa\sing nuclear charge across a period

D. Decrea\sing atomic mass across a period

Correct Answer: C

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Question 12

A sample of an ideal gas is heated from 300 K to 400 K at cons\tant volume. What is the ratio of the final pressure to the initial pressure?

A. 1:1

B. 1:2

Correct C. 2:1

D. 3:1

Correct Answer: C

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Question 13

The reaction between sodium hydroxide and hydrochloric acid is a neutralization reaction. What is the products of this reaction?

Correct A. NaCl + H2O

B. NaOH + HCl

C. NaCl + H2O + CO2

D. NaOH + HCl + CO2

Correct Answer: A

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Question 14

A solution of 2.0 g of glu\cose in 100 g of water has a boiling point elevation of 0.5°C. What is the molar mass of glu\cose?

Correct A. 180 g/mol

B. 200 g/mol

C. 220 g/mol

D. 240 g/mol

Correct Answer: A

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Question 15

A metal M reacts with oxygen to form a basic oxide MO. The reaction is as follows: 4M + 3O2 → 2MO2. What is the oxidation number of M?

A. +2

Correct B. +3

C. +4

D. +5

Correct Answer: B

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Question 16

At 273 K, 1.00 mol of an ideal gas occupies a volume of 22.4 L. What is the molar volume of the gas at 298 K?

A. 22.4 L

Correct B. 24.8 L

C. 28.8 L

D. 32.4 L

Correct Answer: B

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Question 17

The reaction of hydrogen gas with chlorine gas produces hydrogen chloride gas. If 2.50 g of hydrogen gas reacts with 1.50 g of chlorine gas, what is the limiting reac\tant?

Correct A. Hydrogen gas

B. Chlorine gas

C. Hydrogen chloride gas

D. Neither hydrogen gas nor chlorine gas is the limiting reac\tant.

Correct Answer: A

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Question 18

A solution contains 0.500 M NaCl. What is the concentration of Cl- ions in the solution?

A. 0.250 M

Correct B. 0.500 M

C. 0.750 M

D. 1.00 M

Correct Answer: B

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Question 19

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

Correct A. -110.5 kJ/mol

B. -393.5 kJ/mol

C. -74.8 kJ/mol

D. -283.5 kJ/mol

Correct Answer: A

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Question 20

A 1.00 M solution of HCl is prepared by dissolving 36.5 g of HCl in enough water to make 1.00 L of solution. What is the molarity of the solution?

A. 0.500 M

Correct B. 1.00 M

C. 1.50 M

D. 2.00 M

Correct Answer: B

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Question 21

The rate cons\tant of 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. 0.01 M

B. 0.02 M

C. 0.03 M

D. 0.04 M

Correct Answer: A

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Question 22

A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. If the density of the solution is 1.2 g/mL, what is the molar mass of the polymer?

A. 1000 g/mol

B. 2000 g/mol

Correct C. 3000 g/mol

D. 4000 g/mol

Correct Answer: C

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Question 23

A solution of HCl is titrated with a solution of NaOH. If 25 mL of 0.1 M HCl is required to reach the equivalence point, what is the concentration of the NaOH solution?

A. 0.05 M

Correct B. 0.1 M

C. 0.15 M

D. 0.2 M

Correct Answer: B

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Question 24

A 2.5 g sample of a metal is heated in a crucible until it reaches a temperature of 1000°C. If the specific heat capacity of the metal is 0.1 J/g°C, what is the energy required to heat the metal?

A. 250 J

B. 500 J

Correct C. 750 J

D. 1000 J

Correct Answer: C

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Question 25

A 1.5 g sample of a gas is collected over water at a temperature of 20°C and a pressure of 1 atm. If the vapor pressure of water at 20°C is 0.02 atm, what is the partial pressure of the gas?

A. 0.98 atm

B. 0.99 atm

Correct C. 1.00 atm

D. 1.01 atm

Correct Answer: C

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