POST UTME ESUT 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 10.0 L sample of a gas at 2.00 atm and 25°C is compressed to 5.00 L. What is the final pressure of the gas?
A. 4.00 atm
B. 5.00 atm
C. 6.00 atm
D. 8.00 atm
Question 2
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, ΔHf(Ca(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
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 H2O(l) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and that of O2(g) is 0 kJ/mol?
A. -285.8 kJ/mol
B. -241.8 kJ/mol
C. -393.5 kJ/mol
D. -572.8 kJ/mol
Question 4
A polymer has a molecular weight of 100,000 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 5
A sample of CO2 gas is collected over water at 25°C and 1 atm. If the partial pressure of CO2 is 0.75 atm, calculate the mole \fraction of CO2 in the gas mixture.
A. 0.6
B. 0.7
C. 0.8
D. 0.9
Question 6
A solution contains 0.50 M NaCl and 0.25 M CaCl2. What is the concentration of Cl- ions in the solution?
A. 0.375 M
B. 0.500 M
C. 0.625 M
D. 0.750 M
Question 7
The s\tandard enthalpy of formation of NH3(g) is -45.9 kJ/mol. What is the s\tandard enthalpy of formation of N2(g) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol?
A. -72.4 kJ/mol
B. -45.9 kJ/mol
C. 0 kJ/mol
D. 72.4 kJ/mol
Question 8
A 1.5 g sample of a metal chloride (MCl2) is dissolved in 20 mL of water. If the resulting solution has a conductivity of 0.25 S/m, what is the molar conductivity of the solution?
A. 0.5 S m^2/mol
B. 1 S m^2/mol
C. 2 S m^2/mol
D. 5 S m^2/mol
Question 9
A solution of FeCl3 is electrolyzed u\sing a platinum electrode. What is the half-reaction that occurs at the anode?
A. 2H2O(l) → O2(g) + 4H+(aq) + 4e-
B. 2H2O(l) → 2H2(g) + O2(g)
C. Fe3+(aq) + 3e- → Fe(s)
D. 2H+(aq) + 2e- → H2(g)
Question 10
A 5.00 L sample of a gas at 3.00 atm and 30°C is heated to 50°C. What is the final pressure of the gas?
A. 3.50 atm
B. 4.00 atm
C. 4.50 atm
D. 5.00 atm
Question 11
A sample of a polymer has a molecular weight of 50000 g/mol. If 2.5 g of the polymer is dissolved in 50 mL of a solvent, what is the concentration of the solution in g/L?
A. 20 g/L
B. 50 g/L
C. 100 g/L
D. 200 g/L
Question 12
A solution of NaOH is titrated with HCl. The pH of the solution at the equivalence point is 7. What is the concentration of the NaOH solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 13
A 2.0 M solution of HCl is mixed with a 2.0 M solution of NaOH. Calculate the pH of the resulting solution.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 14
The reaction of sodium (Na) with water (H2O) is highly exothermic. What is the primary product of this reaction?
A. Sodium hydroxide (NaOH)
B. Sodium chloride (NaCl)
C. Hydrogen gas (H2)
D. Sodium oxide (Na2O)
Question 15
A 2.00 g sample of a metal is heated in a crucible to produce a 1.50 g sample of the metal oxide. What is the percentage yield of the metal oxide?
A. 75%
B. 80%
C. 85%
D. 90%

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