POST UTME UNILAG 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of gas occupies a volume of 2.5 L at a pressure of 1.5 atm. What is the pressure of the gas when the volume is reduced to 1.0 L?
A. 3.0 atm
B. 4.0 atm
C. 5.0 atm
D. 6.0 atm
Question 2
A 2.0 M solution of NaOH is titrated with a 1.0 M solution of HCl. What is the pH of the solution after 25 mL of HCl has been added?
A. 2
B. 3
C. 4
D. 5
Question 3
A 2.0 M solution of NaOH is titrated with a 1.0 M solution of HCl. What is the pH of the solution after 50 mL of HCl has been added?
A. 1
B. 2
C. 3
D. 4
Question 4
The s\tandard enthalpy of formation \( ΔH_f^circ \) for NO2(g) is 33.2 kJ/mol. The s\tandard enthalpy of formation \( ΔH_f^circ \) for O2(g) is 0 kJ/mol. Calculate the s\tandard enthalpy of formation \( ΔH_f^circ \) for NO(g) u\sing Hess's law.
A. 90.29 kJ/mol
B. 90.29 kJ/mol
C. 90.29 kJ/mol
D. 90.29 kJ/mol
Question 5
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 6
The s\tandard entropy change \( ΔS^circ \) for the reaction: 2NO(g) + O2(g) → 2NO2(g) is -143.5 J/mol·K. Calculate the s\tandard Gibbs free energy change \( ΔG^circ \) for the reaction at 298 K.
A. -114.1 kJ/mol
B. -114.1 kJ/mol
C. -114.1 kJ/mol
D. -114.1 kJ/mol
Question 7
The equilibrium cons\tant (Kc) for a reaction is a measure of the ______________ of the reaction.
A. rate
B. extent
C. equilibrium position
D. concentration
Question 8
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M HCl is titrated with 0.100 M NaOH, what is the number of moles of HCl that react with NaOH?
A. 0.0025 mol
B. 0.0026 mol
C. 0.0027 mol
D. 0.0028 mol
Question 9
A solution of HCl is prepared by dissolving 25 g of HCl in 100 cm³ of water. Calculate the concentration of the solution in terms of molarity.
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 10
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 11
The diagram below shows a pH meter. What is the purpose of the pH meter?
A. To measure the pH of a solution
B. To measure the volume of a solution
C. To mix two solutions
D. To measure the temperature of a solution
Question 12
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M HCl is titrated with 0.100 M NaOH, what is the pH of the solution after the addition of 25.0 mL of NaOH?
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 13
A 10 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 5 mL of NaOH?
A. 1
B. 2
C. 3
D. 4
Question 14
A 25 mL sample of 0.5 M NaOH is titrated with 0.5 M HCl. What is the pH of the solution after the addition of 20 mL of HCl?
A. 2
B. 3
C. 4
D. 5
Question 15
The s\tandard Gibbs free energy change \( ΔG^circ \) for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K is -114.1 kJ/mol. Calculate the equilibrium cons\tant (K) for the reaction.
A. 1.1 × 10^5
B. 1.1 × 10^5
C. 1.1 × 10^5
D. 1.1 × 10^5

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