POST UTME UNIBEN 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A gas is confined to a container with a volume of 2.5 L. If the temperature of the gas is increased from 20°C to 50°C, calculate the new volume of the gas, assuming the pressure remains cons\tant.
A. 3.5 L
B. 4.0 L
C. 4.5 L
D. 5.0 L
Question 2
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the number of moles of NaOH required to reach the equivalence point.
A. 0.0025
B. 0.0050
C. 0.0075
D. 0.0100
Question 3
A sample of hydrogen gas (H2) is collected over water at a temperature of 20°C and a pressure of 1 atm. If the volume of the gas is 2.5 L, calculate the partial pressure of the hydrogen gas.
A. 0.5 atm
B. 0.6 atm
C. 0.7 atm
D. 0.8 atm
Question 4
The boiling point of a subs\tance is the temperature at which the vapor pressure of the subs\tance equals the surrounding pressure. Which of the following is an example of a subs\tance with a high boiling point?
A. H2O
B. CO2
C. CH4
D. O2
Question 5
A 2.00 g sample of a metal oxide is heated in a crucible until it is completely reduced to the metal. If the mass of the metal is 1.50 g, what is the percentage of the metal in the original oxide?
A. 75.0
B. 80.0
C. 85.0
D. 90.0
Question 6
A 2.5 M solution of HCl is electrolyzed u\sing a platinum electrode. What is the mass of Cl2 gas produced at the anode in 2 hours?
A. 0.25 g
B. 0.50 g
C. 1.00 g
D. 2.00 g
Question 7
What is the major product of the reaction between 2-methylpropane and chlorine?
A. 2-chloro-2-methylpropane
B. 2-chloro-2-methyl-1-propane
C. 2-chloro-1-methylpropane
D. 2-chloro-1-methyl-2-propane
Question 8
Determine the number of moles of CO2 produced when 2.5 g of calcium carbonate (CaCO3) is completely decomposed at cons\tant pressure and temperature.
A. 0.05 mol
B. 0.10 mol
C. 0.15 mol
D. 0.20 mol
Question 9
What is the oxidation state of sulfur in the compound SO2Cl2?
A. +4
B. +2
C. +6
D. +8
Question 10
A sample of oxygen gas (O2) is collected over water at a temperature of 20°C and a pressure of 1 atm. If the volume of the gas is 2.5 L, calculate the partial pressure of the oxygen gas.
A. 0.5 atm
B. 0.6 atm
C. 0.7 atm
D. 0.8 atm
Question 11
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 12
A redox reaction involves the transfer of electrons from one species to another. Which of the following is an example of a redox reaction?
A. 2Na + Cl2 → 2NaCl
B. 2H2 + O2 → 2H2O
C. Zn + CuSO4 → ZnSO4 + Cu
D. Fe + CuSO4 → FeSO4 + Cu
Question 13
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 500. What is the molar mass of the repeating unit?
A. 100 g/mol
B. 200 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 14
The density of a subs\tance is the mass per unit volume of the subs\tance. Which of the following is an example of a subs\tance with a high density?
A. H2O
B. CO2
C. CH4
D. O2
Question 15
The equilibrium cons\tant (Kc) is a measure of the extent to which a chemical reaction proceeds. Which of the following is an example of a reaction with a high equilibrium cons\tant (Kc)?
A. N2 + O2 → 2NO
B. 2H2 + O2 → 2H2O
C. CaCO3 → CaO + CO2
D. H2 + I2 → 2HI

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