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POST UTME UI 2018 Chemistry | Objective

Are you preparing for POST UTME UI 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.

Practice these randomly selected questions to test your readiness.

Question 1

Determine the number of unpaired electrons in the ground state of the chromium ion, Cr3+.

A. 0

Correct B. 1

C. 2

D. 3

Correct Answer: B

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Question 2

A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the addition of 20.0 mL of NaOH?

A. 2.00

B. 2.50

Correct C. 3.00

D. 3.50

Correct Answer: C

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Question 3

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

B. -110.5

C. -110.5

D. -110.5

Correct Answer: A

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Question 4

A 2.50 g sample of a subs\tance is found to have a mass of 2.50 g when placed in a 100 mL beaker. What is the density of the subs\tance?

A. 1.00

B. 1.50

C. 2.00

Correct D. 2.50

Correct Answer: D

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Question 5

A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution?

A. 1.00

Correct B. 2.00

C. 3.00

D. 4.00

Correct Answer: B

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Question 6

Determine the solubility of BaSO4 in 0.1M Na2SO4 solution at 25°C, given that the solubility product cons\tant (Ksp) of BaSO4 is 1.1 × 10^\( -10 \).

A. 1.0 × 10^\( -3 \) M

Correct B. 1.0 × 10^\( -4 \) M

C. 1.0 × 10^\( -5 \) M

D. 1.0 × 10^\( -6 \) M

Correct Answer: B

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Question 7

A 2.50 L flask contains 0.250 mol of an ideal gas at 25°C. Calculate the pressure of the gas, given that the gas cons\tant (R) is 0.0821 L atm/mol K.

Correct A. 1.01 × 10^2 atm

B. 1.01 × 10^3 atm

C. 1.01 × 10^4 atm

D. 1.01 × 10^5 atm

Correct Answer: A

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Question 8

The s\tandard enthalpy of formation (ΔHf) of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C(s) to form CO2(g).

A. -393.5 kJ

B. -393.5 kJ/mol

Correct C. -393.5 kJ/mol C

D. -393.5 kJ/mol CO2

Correct Answer: C

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Question 9

A 1.00 M solution of NaOH is mixed with a 1.00 M solution of HCl. Calculate the pH of the resulting solution.

A. 1.00

Correct B. 2.00

C. 3.00

D. 4.00

Correct Answer: B

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Question 10

A 2.00 L flask contains 0.500 mol of an ideal gas at 25°C. Calculate the number of moles of gas that must be added to the flask to increase the pressure by a factor of 2.

A. 0.250 mol

B. 0.500 mol

Correct C. 0.750 mol

D. 1.00 mol

Correct Answer: C

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Question 11

The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of C(s) to form CO2(g).

A. 393.5 kJ/mol

Correct B. -393.5 kJ/mol

C. 0 kJ/mol

D. 1.5 kJ/mol

Correct Answer: B

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Question 12

A solution contains 0.1 M NaCl. What is the concentration of Cl- ions in the solution?

Correct A. 0.05 M

B. 0.1 M

C. 0.2 M

D. 0.5 M

Correct Answer: A

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Question 13

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

A. 25 g

Correct B. 50 g

C. 75 g

D. 100 g

Correct Answer: B

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Question 14

A 2.0 L flask contains 0.5 mol of N2(g) at 25°C. What is the pressure of the gas in the flask?

A. 0.1 atm

Correct B. 0.5 atm

C. 1.0 atm

D. 2.0 atm

Correct Answer: B

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Question 15

A solution contains 0.1 M HCl. What is the pH of the solution?

Correct A. 1

B. 2

C. 3

D. 4

Correct Answer: A

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Question 16

A mixture of 2.50 g of an unknown metal oxide and 2.50 g of CaO is heated in a crucible until the oxide decomposes completely. The mass of the remaining solid is 4.75 g. What is the empirical formula of the unknown metal oxide?

Correct A. MgO

B. CaO

C. FeO

D. CuO

Correct Answer: A

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Question 17

A solution containing 2.5 g of NaCl is mixed with 250 mL of water. What is the molarity of the resulting solution?

A. 0.1 M

B. 0.5 M

Correct C. 1.0 M

D. 2.0 M

Correct Answer: C

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Question 18

A 2.00 L flask contains a gas at 2.00 atm and 25°C. What is the pressure of the gas in a 1.00 L flask at 25°C?

A. 1.00 atm

Correct B. 2.00 atm

C. 3.00 atm

D. 4.00 atm

Correct Answer: B

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Question 19

A 2.00 g sample of a metal is heated in a crucible until it is completely oxidized. The mass of the resulting oxide is 4.00 g. What is the empirical formula of the metal?

A. Mg

B. Ca

Correct C. Fe

D. Cu

Correct Answer: C

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Question 20

A solution containing 1.00 g of glu\cose is mixed with 100 mL of water. What is the molarity of the resulting solution?

A. 0.1 M

B. 0.5 M

Correct C. 1.0 M

D. 2.0 M

Correct Answer: C

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Question 21

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.

Correct A. -1206.60 kJ/mol

B. -1206.60 kJ/mol

C. -1206.60 kJ/mol

D. -1206.60 kJ/mol

Correct Answer: A

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Question 22

A 2.50 L flask contains 0.500 mol of an ideal gas at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.

Correct A. 1.01 x 10^3 Pa

B. 1.01 x 10^3 Pa

C. 1.01 x 10^3 Pa

D. 1.01 x 10^3 Pa

Correct Answer: A

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Question 23

A solution contains 0.100 M NaCl. Calculate the concentration of Cl- ions in the solution.

Correct A. 0.100 M

B. 0.100 M

C. 0.100 M

D. 0.100 M

Correct Answer: A

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Question 24

A 50.0 mL sample of a solution containing 0.500 M HCl is titrated with 0.100 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.

Correct A. 50.0 mL

B. 50.0 mL

C. 50.0 mL

D. 50.0 mL

Correct Answer: A

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Question 25

A 2.00 L flask contains 0.500 mol of an ideal gas at 298 K. Calculate the number of moles of gas present u\sing the ideal gas law.

Correct A. 0.250 mol

B. 0.250 mol

C. 0.250 mol

D. 0.250 mol

Correct Answer: A

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