POST UTME MADONNA UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The reaction of sodium with water is represented by the equation: ( 2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g) ). What is the type of reaction?
A. Synthesis reaction
B. Decomposition reaction
C. Single displacement reaction
D. Double displacement reaction
Question 2
A 2.00 M solution of HCl is prepared by dissolving 36.5 g of HCl in 1.00 L of water. What is the pH of the solution?
A. 0.00
B. 1.00
C. 2.00
D. 3.00
Question 3
A 2.50-g sample of a non-metallic element is heated in a crucible until it is completely vaporized. If the vapor density of the element is 4.00 g/L, what is the molar mass of the element?
A. 20.0 g/mol
B. 30.0 g/mol
C. 40.0 g/mol
D. 50.0 g/mol
Question 4
A redox reaction involves the oxidation of Fe2+ to Fe3+ and the reduction of MnO4- to Mn2+. Write the balanced equation for the reaction.
A. Fe2+ + MnO4- → Fe3+ + Mn2+
B. Fe2+ + MnO4- → Fe3+ + Mn2+
C. Fe2+ + MnO4- → Fe3+ + Mn2+
D. Fe2+ + MnO4- → Fe3+ + Mn2+
Question 5
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 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 6
A metal is extracted from its ore through electrolysis. The metal has a s\tandard reduction potential of -0.5 V. What is the minimum voltage required to extract the metal?
A. 0.5 V
B. 0.5 V
C. 0.5 V
D. 0.5 V
Question 7
What is the change in entropy when 1 mole of an ideal gas expands from 1 L to 2 L at cons\tant temperature?
A. -22.4 J/K
B. 22.4 J/K
C. -11.2 J/K
D. 11.2 J/K
Question 8
A sample of air contains 20% O2, 30% N2, and 50% Ar. What is the partial pressure of O2 at a total pressure of 1013 mbar?
A. 203 mbar
B. 303 mbar
C. 403 mbar
D. 503 mbar
Question 9
A 2.50-g sample of a metal is heated in a crucible until it is completely vaporized. If the vapor density of the metal is 10.0 g/L, what is the molar mass of the metal?
A. 50.0 g/mol
B. 60.0 g/mol
C. 70.0 g/mol
D. 80.0 g/mol
Question 10
A sample of an ideal gas at 25°C and 1 atm is heated to 100°C at cons\tant pressure. What is the new volume of the gas?
A. 2.00 L
B. 4.00 L
C. 8.00 L
D. 16.00 L
Question 11
The reaction of H2O2 with NaOH is represented by the equation: H2O2 + 2NaOH → Na2O2 + 2H2O. What is the rate law for this reaction?
A. rate = k[NaOH]^2[H2O2]
B. rate = k[NaOH][H2O2]
C. rate = k[H2O2]^2[NaOH]
D. rate = k[NaOH]^2[H2O2]^2
Question 12
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 13
The diagram below represents a titration setup. What is the purpose of the burette?
A. To measure the volume of the solution
B. To measure the concentration of the solution
C. To measure the pH of the solution
D. To measure the temperature of the solution
Question 14
The polymerization of styrene to polystyrene is an example of a chain reaction. What is the role of the initiator in this reaction?
A. To provide a source of heat
B. To initiate the polymerization reaction
C. To act as a catalyst
D. To provide a source of oxygen
Question 15
A sample of an ideal gas at 25°C and 1 atm is compressed to 2 atm at cons\tant temperature. What is the new volume of the gas?
A. 0.50 L
B. 1.00 L
C. 2.00 L
D. 4.00 L

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