POST UTME OSUSTECH 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Identify the type of reaction represented by the equation: \( 2Na + Cl_2 \rightarrow 2NaCl \).
A. Synthesis reaction
B. Decomposition reaction
C. Single displacement reaction
D. Double displacement reaction
Question 2
A solution of sulfuric acid (H2SO4) is prepared by dissolving 50.0 g of the acid in 100.0 mL of water. If the density of the solution is 1.2 g/mL, what is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 3
A sample of an ideal gas at 25°C and 1 atm expands from 2.0 L to 4.0 L. Calculate the work done by the gas in Joules.
A. 40 J
B. 80 J
C. 120 J
D. 160 J
Question 4
A 0.1 M solution of NaOH is mixed with a 0.1 M solution of HCl. What is the concentration of OH- ions in the resulting solution?
A. 0.05 M
B. 0.10 M
C. 0.15 M
D. 0.20 M
Question 5
A sample of a gas has a volume of 2 L at a pressure of 1 atm. If the pressure is increased to 2 atm, what is the new volume of the gas?
A. 1 L
B. 2 L
C. 4 L
D. 8 L
Question 6
A reaction is represented by the equation: 2A + B → C + 2D. If 1.00 mol of A and 0.500 mol of B are present, what is the limiting reac\tant?
A. A
B. B
C. C
D. D
Question 7
A 0.1 M solution of HCl is prepared by dissolving 3.0 g of HCl in 1.0 L of water. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 8
A sample of a polymer has a molecular weight of 50000 g/mol. If 0.5 g of the polymer is dissolved in 100 mL of solvent, what is the concentration of the solution in g/L?
A. 0.05 g/L
B. 0.5 g/L
C. 5 g/L
D. 50 g/L
Question 9
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution after mixing 50.0 mL of each solution?
A. 0.00
B. 1.00
C. 2.00
D. 3.00
Question 10
A sample of a non-metallic oxide is found to have a mass of 2.5 g and a volume of 5.0 mL. If the density of the oxide is 3.0 g/mL, what is the molar mass of the oxide?
A. 60 g/mol
B. 80 g/mol
C. 100 g/mol
D. 120 g/mol
Question 11
A 0.1 M solution of HCl is mixed with a 0.1 M solution of NaOH in a 1:1 ratio. What is the concentration of the resulting solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 12
The polymerization of styrene to polystyrene involves the addition of a monomer unit to the growing polymer chain. If the rate of polymerization is 0.05 mol/L·min, and the initial concentration of styrene is 1.0 mol/L, what is the concentration of styrene after 10 minutes?
A. 0.95 mol/L
B. 0.90 mol/L
C. 0.85 mol/L
D. 0.80 mol/L
Question 13
Determine the s\tandard electrode potential of the cell represented by the following reaction: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O. Given that the s\tandard electrode potential of the MnO4-/Mn2+ couple is +1.23 V.
A. +1.23 V
B. +1.48 V
C. +1.93 V
D. +2.18 V
Question 14
A 0.500 g sample of a metal oxide is heated in a crucible until it decomposes completely. The mass of the metal obtained is 0.350 g. If the metal oxide has a molar mass of 120 g/mol and the metal has a molar mass of 40 g/mol, calculate the percentage yield of the metal.
A. 80%
B. 85%
C. 90%
D. 95%
Question 15
A sample of a polymer has a molecular weight of 100,000 g/mol. If 0.500 g of the polymer is dissolved in 100.0 mL of solvent, what is the concentration of the solution in g/L?
A. 0.500 g/L
B. 1.00 g/L
C. 2.00 g/L
D. 5.00 g/L

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