POST UTME ACHIEVERS UNIVERSITY 2020 Chemistry | Objective

Are you preparing for POST UTME ACHIEVERS UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2020 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1
A 0.5 M solution of a weak acid HA is titrated with 0.5 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, what is the initial volume of the acid solution?
A. 10 mL
B. 20 mL
Correct C. 30 mL
D. 40 mL

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 2
A polymer has a degree of polymerization (n) of 1000. If the molecular weight of the repeating unit is 200 g/mol, what is the molecular weight of the polymer?
Correct A. 2.00 x 10^5 g/mol
B. 2.00 x 10^6 g/mol
C. 2.00 x 10^7 g/mol
D. 2.00 x 10^8 g/mol

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 3
A reaction has a rate cons\tant (k) of 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. 0.05 M
B. 0.10 M
C. 0.15 M
D. 0.20 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 4
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution?
A. 1
Correct B. 2
C. 3
D. 4

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 5
A 1.0 M solution of a weak base B is titrated with 1.0 M HCl. If 20 mL of HCl is required to reach the equivalence point, what is the initial volume of the base solution?
A. 10 mL
B. 20 mL
Correct C. 30 mL
D. 40 mL

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 6
Determine the number of moles of oxygen gas (O2) required to react with 2.5 moles of propane (C3H8) according to the balanced equation: 2C3H8 + 19O2 → 12CO2 + 14H2O.
A. 1.5 moles
B. 2.5 moles
Correct C. 3.75 moles
D. 4.5 moles

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 7
A 0.5 M solution of sodium hydroxide (NaOH) is prepared by dissolving 10.0 g of NaOH in 1.0 L of water. What is the concentration of the solution in terms of molarity?
A. 0.1 M
Correct B. 0.5 M
C. 1.0 M
D. 2.0 M

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 8
A 2.0 g sample of a polymer is dissolved in 100 mL of a solvent. The solution is then diluted to a total volume of 500 mL. What is the concentration of the polymer solution in terms of g/L?
A. 0.4 g/L
Correct B. 0.8 g/L
C. 1.2 g/L
D. 1.6 g/L

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 9
A gas at 25°C and 1 atm is compressed to 5 atm. What is the new volume of the gas?
A. 0.2 L
B. 0.4 L
C. 0.6 L
Correct D. 0.8 L

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 10
A metal rod is heated to 800°C and then quenched in water. The resulting metal is then annealed at 300°C for 2 hours. What is the final microstructure of the metal?
A. Ferrite
B. Pearlite
Correct C. Martensite
D. Bainite

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 11
Determine the molar mass of a polymer with the following molecular formula: C10H8O4. Given that the atomic masses of carbon, hydrogen, and oxygen are 12.01 g/mol, 1.01 g/mol, and 16.00 g/mol, respectively.
A. 120.12 g/mol
Correct B. 128.12 g/mol
C. 136.12 g/mol
D. 144.12 g/mol

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 12
A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: 2X + Cl2 → 2XCl. If 2.50 g of X reacts with 1.00 g of Cl2, what is the percentage yield of XCl if the molar mass of X is 40.00 g/mol and the molar mass of Cl2 is 70.90 g/mol?
A. 80.00%
B. 85.00%
Correct C. 90.00%
D. 95.00%

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 13
A sample of a gas occupies a volume of 2.50 L at a temperature of 25°C and a pressure of 1.00 atm. If the temperature is increased to 50°C and the pressure is increased to 2.00 atm, what is the new volume of the gas?
A. 3.00 L
B. 3.50 L
Correct C. 4.00 L
D. 4.50 L

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 14
A solution contains 2.50 g of NaCl in 100.0 mL of water. What is the molarity of the solution?
A. 0.100 M
B. 0.200 M
Correct C. 0.300 M
D. 0.400 M

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 15
A sample of a non-metal (X) reacts with oxygen gas to form a white solid. The reaction is as follows: 2X + O2 → 2XO. If 2.50 g of X reacts with 1.00 g of O2, what is the percentage yield of XO if the molar mass of X is 32.00 g/mol and the molar mass of O2 is 32.00 g/mol?
A. 80.00%
B. 85.00%
Correct C. 90.00%
D. 95.00%

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 16
The reaction between nitrogen dioxide and water is an example of a redox reaction. What is the oxidation state of nitrogen in NO2?
A. +2
Correct B. +4
C. +6
D. +8

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 17
A 2.5 L flask contains 0.5 mol of an ideal gas at 25°C. What is the pressure of the gas?
A. 1.0 atm
B. 2.0 atm
Correct C. 2.5 atm
D. 3.0 atm

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 18
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. What is the s\tandard enthalpy of combustion of 1 mol of CO?
A. -100.5 kJ/mol
Correct B. -110.5 kJ/mol
C. -120.5 kJ/mol
D. -130.5 kJ/mol

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 19
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the solution?
A. 10.0
Correct B. 11.0
C. 12.0
D. 13.0

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 20
A 50 mL sample of a solution contains 0.5 g of NaCl. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
Correct C. 0.5 M
D. 1.0 M

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 21
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. At the equivalence point, the pH of the solution is 7. Calculate the initial volume of the acid solution in liters.
A. 0.05 L
Correct B. 0.1 L
C. 0.2 L
D. 0.5 L

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 22
A metal M reacts with chlorine gas to form a white solid MX. The molar mass of M is 55 g/mol, and the molar mass of MX is 142 g/mol. What is the oxidation state of M in MX?
A. +1
B. +2
Correct C. +3
D. +4

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 23
A solution of HCl is 0.1 M. If 25 mL of this solution is diluted to 100 mL, what is the new concentration of HCl in the solution?
Correct A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 24
A 2.0 g sample of a metal M is heated in a crucible until it is completely oxidized. The mass of the crucible and the oxide formed is 3.2 g. What is the molar mass of M?
A. 40 g/mol
Correct B. 55 g/mol
C. 70 g/mol
D. 80 g/mol

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics
Question 25
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. At the equivalence point, the pH of the solution is 7. Calculate the initial volume of the acid solution in liters.
A. 0.05 L
Correct B. 0.1 L
C. 0.2 L
D. 0.5 L

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub:
Chat with Support