POST UTME COVENANT UNIVERSITY 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of a non-metallic element has a mass of 25.0 g and a volume of 5.00 mL. What is the density of the element?
A. 5.00 g/mL
B. 5.50 g/mL
C. 6.00 g/mL
D. 6.50 g/mL
Question 2
A 5.00 g sample of a metal hydroxide is treated with 20.0 mL of 1.00 M HCl. Calculate the mass of the metal chloride produced.
A. 2.50 g
B. 3.00 g
C. 3.50 g
D. 4.00 g
Question 3
A 2.0 g sample of a metal is heated in a crucible. Calculate the mass of the metal after 1 hour.
A. 1.5 g
B. 2.0 g
C. 2.5 g
D. 3.0 g
Question 4
The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of copper in the product Cu(s)?
A. +1
B. 0
C. +2
D. -1
Question 5
The diagram below shows a setup for the electrolysis of water. What is the purpose of the anode in this setup?
A. To release oxygen gas
B. To release hydrogen gas
C. To release chlorine gas
D. To release bromine gas
Question 6
A 2.5 g sample of a polymer is dissolved in 100 mL of a solvent. Calculate the molar mass of the polymer.
A. 100 g/mol
B. 200 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 7
A 0.1 M solution of a weak base, B, has a pH of 8.5. If 10 mL of 1 M HCl is added to 90 mL of the base solution, what is the pH of the resulting solution?
A. 7.5
B. 8.5
C. 9.5
D. 10.5
Question 8
A 1.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 1 L of water. Calculate the molarity of the solution.
A. 0.5
B. 1.0
C. 1.5
D. 2.0
Question 9
The reaction between sulfur dioxide and oxygen to form sulfur trioxide is highly exothermic. What is the value of ΔH for this reaction, given that the s\tandard enthalpy of formation of SO2 is -296.8 kJ/mol and the s\tandard enthalpy of formation of SO3 is -395.7 kJ/mol?
A. -99.9 kJ/mol
B. -99.1 kJ/mol
C. -98.3 kJ/mol
D. -97.5 kJ/mol
Question 10
A 5.00 g sample of a metal hydroxide is dissolved in 100.0 mL of water to produce a solution with a pH of 10.5. What is the molar mass of the metal hydroxide?
A. 100.0 g/mol
B. 120.0 g/mol
C. 140.0 g/mol
D. 160.0 g/mol
Question 11
A cell is placed in a 0.1 M solution of KCl. Calculate the potential of the cell.
A. -0.1 V
B. -0.2 V
C. -0.3 V
D. -0.4 V
Question 12
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.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 13
The half-life of a radioactive subs\tance is 5 days. If 100 mg of the subs\tance is present initially, how much of the subs\tance will remain after 15 days?
A. 50 mg
B. 25 mg
C. 12.5 mg
D. 6.25 mg
Question 14
A 2.50 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 2.00 g. Calculate the percentage yield of the metal oxide.
A. 80.0%
B. 85.0%
C. 90.0%
D. 95.0%
Question 15
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CO(g) if the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol.
A. -110.5
B. -110.5 kJ/mol
C. -110.5 kJ/mol CO
D. -110.5 kJ/mol CO2

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