POST UTME LEAD CITY UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of a metal with the atomic number 12 is analyzed by X-ray fluorescence. The wavelength of the X-ray emitted is 1.5 Å. What is the energy of the X-ray?
A. 1.5 eV
B. 3.0 eV
C. 4.5 eV
D. 6.0 eV
Question 2
A 1.00 L flask contains 0.500 mol of CO2 at 298 K. What is the pressure of the gas?
A. 0.500 atm
B. 0.500 atm
C. 0.500 atm
D. 0.500 atm
Question 3
The diagram below shows a titration setup.
A. The burette contains the acid.
B. The beaker contains the acid.
C. The burette contains the base.
D. The beaker contains the base.
Question 4
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. If 25 mL of the acid is titrated with 15 mL of the base, what is the pH of the resulting solution?
A. 3
B. 4
C. 5
D. 6
Question 5
Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K, given that the rate cons\tant at 298 K is 1.5 × 10^\( -2 \) s^\( -1 \) and the activation energy (Ea) is 2.5 × 10^5 J/mol.
A. 1.2 × 10^\( -2 \) s^\( -1 \)
B. 1.5 × 10^\( -2 \) s^\( -1 \)
C. 1.8 × 10^\( -2 \) s^\( -1 \)
D. 2.0 × 10^\( -2 \) s^\( -1 \)
Question 6
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. If 25 mL of the acid is required to reach the equivalence point, calculate the number of moles of the acid used.
A. 0.0025 mol
B. 0.005 mol
C. 0.0075 mol
D. 0.01 mol
Question 7
A 0.1 M solution of a weak base B is titrated with 0.1 M HCl. If 20 mL of the base solution requires 15 mL of HCl for neutralization, calculate the number of moles of B in 1 L of the base solution.
A. 0.01 mol
B. 0.02 mol
C. 0.03 mol
D. 0.04 mol
Question 8
A 2.50 g sample of a polymer is dissolved in 50.0 mL of a solvent. If the solution has a density of 1.00 g/mL, what is the concentration of the solution in g/L?
A. 10.0 g/L
B. 20.0 g/L
C. 30.0 g/L
D. 40.0 g/L
Question 9
A solution of NaOH is prepared by dissolving 10 g of NaOH in 100 g of water. What is the molarity of the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 10
A solution containing 0.1 M NaCl is electrolyzed u\sing a current of 0.5 A for 2 hours. Calculate the mass of Cl2 gas produced at the anode.
A. 0.1 g
B. 0.2 g
C. 0.3 g
D. 0.4 g
Question 11
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If 20 mL of the acid solution requires 15 mL of NaOH for neutralization, calculate the number of moles of HA in 1 L of the acid solution.
A. 0.01 mol
B. 0.02 mol
C. 0.03 mol
D. 0.04 mol
Question 12
A 2.5 M solution of H2SO4 is prepared by dissolving 2.5 g of H2SO4 in 100 mL of water. What is the molarity of the solution?
A. 2.0 M
B. 2.5 M
C. 3.0 M
D. 3.5 M
Question 13
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of vaporization of 1 mol of H2O(l) to form H2O(g).
A. -44.0 kJ
B. -44.5 kJ
C. -45.0 kJ
D. -45.5 kJ
Question 14
A 25.0 mL sample of a solution containing 0.500 M sodium hydroxide is titrated with 0.500 M hydrochloric acid. What is the pH of the solution after the titration?
A. 7.00
B. 8.00
C. 9.00
D. 10.0
Question 15
A 1.0 M solution of NaOH is titrated with a 0.5 M solution of HCl. If 20 mL of the acid is required to reach the equivalence point, what is the pH of the resulting solution?
A. 2.5
B. 3.5
C. 4.5
D. 5.5

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