POST UTME UNIOSUN 2022 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The half-reaction for the reduction of NO3- is NO3- + 4H+ + 3e- → NO + 2H2O. What is the s\tandard electrode potential of the couple NO3-/NO?
A. 0.87 V
B. 0.87 V
C. 0.87 V
D. 0.87 V
Question 2
A 2.5 L flask contains 0.5 mol of an ideal gas at 25°C. What is the pressure of the gas in the flask?
A. 1.01 × 10^5 Pa
B. 2.02 × 10^5 Pa
C. 3.03 × 10^5 Pa
D. 4.04 × 10^5 Pa
Question 3
What is the major product of the reaction between 2-methylpropene and HCl?
A. 2-chloro-2-methylpropane
B. 2-chloro-2-methylbu\tane
C. 2-chloro-3-methylbu\tane
D. 2-chloro-2-methylpen\tane
Question 4
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -393.5 kJ/mol
C. -110.5 kJ/mol - 393.5 kJ/mol
D. -393.5 kJ/mol + 110.5 kJ/mol
Question 5
The reaction 2NO(g) + O2(g) → 2NO2(g) is carried out in a 1.0 L flask at 298 K. If the initial pressure of NO is 0.50 atm, what is the equilibrium pressure of NO2?
A. 0.25 atm
B. 0.50 atm
C. 1.00 atm
D. 2.00 atm
Question 6
Determine the s\tandard Gibbs free energy change for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K and 1 atm, given that ΔH° = -114.1 kJ/mol and ΔS° = 137.2 J/mol·K.
A. -114.1 kJ/mol
B. -114.1 kJ/mol + 137.2 J/mol·K
C. -114.1 kJ/mol - 137.2 J/mol·K
D. -114.1 kJ/mol + 137.2 kJ/mol
Question 7
A 1.00 M solution of H2SO4 is titrated with 0.500 M NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 8
What is the s\tandard enthalpy of formation of CO2(g)?
A. -393.5 kJ/mol
B. +393.5 kJ/mol
C. -393.5 kJ/mol
D. +393.5 kJ/mol
Question 9
A 0.1 M solution of HCl is mixed with a 0.1 M solution of NaOH. If the reaction is allowed to proceed to completion, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 10
A 0.500 M solution of NH3 is electrolyzed u\sing a platinum electrode. The cell potential is 1.33 V. What is the mass of N2 produced at the anode after 1.00 hour?
A. 0.100 g
B. 0.200 g
C. 0.500 g
D. 1.00 g
Question 11
Determine the oxidation state of nitrogen in the compound NO2.
A. +1
B. +2
C. +3
D. +4
Question 12
A sample of an ideal gas is heated from 300 K to 400 K at cons\tant volume. What is the ratio of the final pressure to the initial pressure?
A. 1.33
B. 2.00
C. 3.00
D. 4.00
Question 13
A 0.1 M solution of HCl is mixed with a 0.1 M solution of NaOH. If the reaction is allowed to proceed to completion, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 14
The rate cons\tant for the decomposition of N2O5 is 2.50 × 10^\( -3 \) s^\( -1 \) at 298 K. What is the half-life of the reaction?
A. \( 2.80 \times 10^3 \) s
B. \( 2.80 \times 10^2 \) s
C. \( 2.80 \times 10^1 \) s
D. \( 2.80 \times 10^\( -1 \ \) ) s
Question 15
A 1.00 M solution of HCl is prepared by dissolving 36.5 g of HCl in enough water to make 1.00 L of solution. What is the pH of the solution?
A. 0.000
B. 1.00
C. 2.00
D. 3.00

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