POST UTME LEAD CITY UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Determine the molar mass of a polymer with the repeating unit (C6H5O2)n. Given that the molar mass of the repeating unit is 138.12 g/mol, calculate the molar mass of the polymer.
A. 138.12 g/mol
B. 276.24 g/mol
C. 414.36 g/mol
D. 552.48 g/mol
Question 2
A 0.500 M solution of HCl is prepared by dissolving 10.0 g of HCl in 1.00 L of water. Calculate the molar solubility of HCl.
A. 0.100 M
B. 0.500 M
C. 1.00 M
D. 2.00 M
Question 3
A 2.5 g sample of a compound containing only carbon and hydrogen is found to have a mass of 1.25 g when burned in oxygen to produce carbon dioxide and water. Calculate the empirical formula of the compound.
A. CH2
B. CH3
C. C2H4
D. C2H6
Question 4
A 2.5 g sample of a non-metallic oxide, X2O3, is dissolved in 50 mL of 0.1 M HCl. The resulting solution has a pH of 1.75. Calculate the molar mass of the oxide.
A. 150 g/mol
B. 200 g/mol
C. 250 g/mol
D. 300 g/mol
Question 5
A 1.0 M solution of a weak acid, HA, has a pH of 3.25. Calculate the value of Ka for the acid.
A. 1.2 x 10^\( -5 \)
B. 1.5 x 10^\( -5 \)
C. 1.8 x 10^\( -5 \)
D. 2.1 x 10^\( -5 \)
Question 6
A 2.00 M solution of NaOH is prepared by dissolving 40.0 g of NaOH in 1.00 L of water. Calculate the molar solubility of NaOH.
A. 0.200 M
B. 0.500 M
C. 1.00 M
D. 2.00 M
Question 7
A 0.500 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide is 0.350 g. Calculate the percentage of metal in the original sample.
A. 15.0%
B. 20.0%
C. 25.0%
D. 30.0%
Question 8
A 25 mL sample of a 0.1 M solution of sodium hydroxide (NaOH) is titrated with a 0.1 M solution of hydrochloric acid (HCl). What is the pH of the resulting solution after the reaction is complete?
A. 7
B. 8
C. 9
D. 10
Question 9
The reaction between H2(g) and Cl2(g) is represented by the equation: H2(g) + Cl2(g) → 2HCl(g). If 1.00 mol of H2(g) reacts with 1.00 mol of Cl2(g), what is the limiting reac\tant?
A. H2(g)
B. Cl2(g)
C. Neither H2(g) nor Cl2(g) is the limiting reac\tant.
D. Both H2(g) and Cl2(g) are the limiting reac\tants.
Question 10
A sample of a polymer has a molecular weight of 50000 g/mol. If 2.5 g of the polymer is dissolved in 100 mL of water, what is the concentration of the solution in g/L?
A. 0.05
B. 0.1
C. 0.2
D. 0.5
Question 11
A solution of 0.1 M NaCl is prepared by dissolving 6.0 g of NaCl in 100 mL of water. What is the concentration of Cl- ions in the solution?
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 12
A gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 25°C. Calculate the volume of the gas at a pressure of 3.0 atm and a temperature of 50°C.
A. 3.0 L
B. 4.0 L
C. 5.0 L
D. 6.0 L
Question 13
A 2.50 g sample of a metal is heated in a crucible to produce a metal oxide. The mass of the metal oxide is 3.25 g. Calculate the percentage of oxygen in the metal oxide.
A. 20.0%
B. 25.0%
C. 30.0%
D. 35.0%
Question 14
A 1.0 M solution of Fe2+ ions is titrated with 1.0 M NaOH. Calculate the pH of the solution after 20 mL of NaOH has been added.
A. 1
B. 2
C. 3
D. 4
Question 15
A 1.0 g sample of a subs\tance is found to have a mass of 0.5 g when heated to 100°C. Calculate the percentage of water in the subs\tance.
A. 20%
B. 30%
C. 40%
D. 50%

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