POST UTME SUMMIT UNIVERSITY 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of H2O(l) from the following reaction: CO(g) + H2(g) → H2O(l) + 393.5 kJ.
A. -285.8 kJ/mol
B. -241.8 kJ/mol
C. -393.5 kJ/mol
D. -285.8 kJ/mol
Question 2
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. -1206.0 kJ/mol
B. -1206.5 kJ/mol
C. -1207.0 kJ/mol
D. -1207.5 kJ/mol
Question 3
A 2.5 M solution of HCl is mixed with a 1.0 M solution of NaOH. Calculate the number of moles of HCl that react with NaOH.
A. 0.005 mol
B. 0.01 mol
C. 0.015 mol
D. 0.02 mol
Question 4
The rate cons\tant (k) for a first-order reaction is related to the half-life \( t_\( 1/2 \ \)) by the equation: \( k = \frac{ln{2}}{t_{1/2}} \). If the half-life of a reaction is 10 minutes, what is the rate cons\tant (k) in units of min^\( -1 \)?
A. 0.0693 min^\( -1 \)
B. 0.693 min^\( -1 \)
C. 6.93 min^\( -1 \)
D. 69.3 min^\( -1 \)
Question 5
A solution contains 0.020 M HCl and 0.030 M NaOH. What is the pH of the solution?
A. ( 2.0 )
B. ( 3.0 )
C. ( 4.0 )
D. ( 5.0 )
Question 6
The concentration of a solution of sodium hydroxide (NaOH) is 0.100 M. If 25.0 mL of this solution is titrated with 0.0500 M hydrochloric acid (HCl), what is the pH of the resulting solution?
A. 9.25
B. 9.50
C. 9.75
D. 10.00
Question 7
A 2.50 g sample of a metal oxide is heated in a crucible until it is completely reduced to its constituent metal and oxygen. If the mass of the metal produced is 1.75 g, what is the empirical formula of the metal oxide?
A. FeO
B. Fe2O3
C. Fe3O4
D. FeO2
Question 8
A 1.00 M solution of HCl is mixed with a 1.00 M solution of NaOH. If the reaction is allowed to go to completion, what is the concentration of the resulting solution?
A. 0.50 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 9
A 2.0 L flask contains 0.10 mol of an ideal gas at 298 K. What is the pressure of the gas in the flask?
A. \( 1.01 \times 10^{5} \) Pa
B. \( 2.02 \times 10^{5} \) Pa
C. \( 3.03 \times 10^{5} \) Pa
D. \( 4.04 \times 10^{5} \) Pa
Question 10
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 11
The rate cons\tant of a first-order reaction is given by \( k = Ae^{-E_a/RT} \). If the activation energy \( E_a \) is 100 kJ/mol, the gas cons\tant ( R ) is 8.314 J/(mol·K), and the temperature ( T ) is 300 K, what is the value of the pre-exponential factor ( A ) if the rate cons\tant ( k ) is 0.05 s\( ^{-1} \)?
A. \( 1.23 \times 10^{10} \)
B. \( 1.23 \times 10^{11} \)
C. \( 1.23 \times 10^{12} \)
D. \( 1.23 \times 10^{13} \)
Question 12
A solution contains 0.250 g of NaCl per 100 mL of solution. What is the molarity of the solution?
A. 0.250 M
B. 0.500 M
C. 1.00 M
D. 2.00 M
Question 13
A 2.50 g sample of a hydrocarbon is burned in a bomb calorimeter, relea\sing 12.5 kJ of heat. If the heat of combustion of the hydrocarbon is 46.0 kJ/g, what is the empirical formula of the hydrocarbon?
A. C_(2)H_(6)
B. C_(3)H_(8)
C. C_(4)H_(10)
D. C_(5)H_(12)
Question 14
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.0 mol of C6H12O6(s).
A. -2800.0 kJ/mol
B. -2800.5 kJ/mol
C. -2801.0 kJ/mol
D. -2801.5 kJ/mol
Question 15
The s\tandard reduction potential of the Mn2+/Mn couple is -1.18 V. What is the s\tandard reduction potential of the Mn3+/Mn couple?
A. -0.90 V
B. -1.18 V
C. -1.45 V
D. -1.70 V

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