POST UTME UNN 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy change for the reaction: CaO(s) + H2O(l) → Ca(OH)2(s) is -63.5 kJ/mol. Calculate the s\tandard entropy change (ΔS°) for the reaction.
A. -0.1 kJ/mol·K
B. -0.2 kJ/mol·K
C. -0.3 kJ/mol·K
D. -0.4 kJ/mol·K
Question 2
The diagram below shows a titration setup. What is the purpose of the burette?
A. To measure the volume of the titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To measure the pH of the solution
Question 3
Calculate the s\tandard enthalpy change for the reaction: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s). Given that ΔH°(Al2O3(s)) = -1675 kJ/mol, ΔH°(Al(s)) = 0 kJ/mol, ΔH°(Fe2O3(s)) = -825 kJ/mol, and ΔH°(Fe(s)) = 0 kJ/mol.
A. -2750 kJ/mol
B. -1750 kJ/mol
C. -275 kJ/mol
D. -175 kJ/mol
Question 4
The s\tandard Gibbs free energy change for the reaction: 2NO(g) + O2(g) → 2NO2(g) is -120 kJ/mol. Calculate the equilibrium cons\tant (K) for the reaction.
A. 10^\( -6 \)
B. 10^\( -3 \)
C. 10^\( -2 \)
D. 10^\( -1 \)
Question 5
A 2.5 M solution of H2SO4 is titrated with 1 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 6
A 2.5 g sample of a subs\tance is dissolved in 50 mL of water. The resulting solution has a conductivity of 0.02 S/m. What is the molar conductivity of the solution?
A. 10
B. 20
C. 30
D. 40
Question 7
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 8
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution after mixing?
A. 1
B. 2
C. 3
D. 4
Question 9
A solution containing 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 10
What is the oxidation state of the underlined atom in the compound H2SO4?
A. +2
B. +4
C. +6
D. +8

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