POST UTME COVENANT UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of polystyrene has a density of 1.05 g/cm3. What is the volume of a 25 g sample of the polymer?
A. 23.81 cm3
B. 24.24 cm3
C. 24.67 cm3
D. 25.1 cm3
Question 2
A reaction between a non-metal and a ha\logen produces a compound with a melting point of 150°C. If the non-metal has an atomic mass of 16 g/mol and the ha\logen has an atomic mass of 35.5 g/mol, what is the empirical formula of the compound?
A. NaCl
B. CaF2
C. H2O
D. CO2
Question 3
A 2.00 L sample of a gas at 27°C and 1.00 atm is compressed to 0.50 L at cons\tant temperature. Calculate the work done on the gas in joules.
A. 1.00 kJ
B. 2.00 kJ
C. 3.00 kJ
D. 4.00 kJ
Question 4
A mixture of 1.0 g of an unknown polymer and 2.0 g of an unknown solvent is dissolved in 50.0 mL of water. The solution is then titrated with 0.1 M HCl. If 20.0 mL of HCl is required to reach the equivalence point, what is the molar mass of the polymer?
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 5
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, how much will remain after 15 years?
A. 12.5 g
B. 25 g
C. 50 g
D. 100 g
Question 6
Determine the number of moles of glu\cose (C6H12O6) present in 250 mL of a 0.5 M solution.
A. 0.25 mol
B. 0.5 mol
C. 1 mol
D. 1.25 mol
Question 7
A 2.00 L sample of a gas at 27°C and 1.00 atm is compressed to 0.50 L at cons\tant temperature. Calculate the work done on the gas in joules.
A. 1.00 kJ
B. 2.00 kJ
C. 3.00 kJ
D. 4.00 kJ
Question 8
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. If the pH of the solution at the equivalence point is 7, calculate the volume of HCl required to reach the equivalence point.
A. 25 cm^3
B. 50 cm^3
C. 75 cm^3
D. 100 cm^3
Question 9
A solution contains 2.00 g of NaCl in 100.0 mL of water. Calculate the molarity of the solution.
A. 0.20 M
B. 0.40 M
C. 0.60 M
D. 0.80 M
Question 10
A metal alloy is composed of 70% Cu and 30% Zn. If 100 g of the alloy is heated to 1000°C, what is the temperature of the alloy when it cools to 500°C?
A. 500°C
B. 600°C
C. 700°C
D. 800°C
Question 11
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. If the molar mass of the polymer is 50,000 g/mol, calculate the number of moles of the polymer dissolved.
A. 0.00005 mol
B. 0.0005 mol
C. 0.005 mol
D. 0.05 mol
Question 12
A solution of 0.1 M NaOH is slowly added to a solution of 0.1 M HCl. If the initial pH of the HCl solution is 1.0, what is the pH of the solution after 10.0 mL of NaOH has been added?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 13
Determine the rate cons\tant (k) for the first-order reaction: A → B, given that the initial concentration of A is 0.1 M and the concentration of A after 10 minutes is 0.05 M. The rate cons\tant is related to the half-life \( t1/2 \) by the equation: k = ln(2) / t1/2.
A. 0.693 min^-1
B. 1.386 min^-1
C. 2.772 min^-1
D. 3.464 min^-1
Question 14
A sample of N2 gas occupies a volume of 2.5 L at a pressure of 1.5 atm. What is the pressure of the gas when its volume is increased to 5.0 L?
A. 0.75 atm
B. 1.0 atm
C. 1.5 atm
D. 2.0 atm
Question 15
A solution contains 0.2 M NaCl and 0.1 M CaCl2. What is the concentration of Cl^- ions in the solution?
A. 0.3 M
B. 0.4 M
C. 0.5 M
D. 0.6 M

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