POST UTME LAUTECH 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1.00 g sample of a non-metallic oxide is analyzed by titration with a solution of sodium hydroxide. The amount of sodium hydroxide required to react with the oxide is 25.0 cm³ of 0.100 M sodium hydroxide solution. Calculate the mass of the oxide.
A. 0.500 g
B. 1.00 g
C. 2.00 g
D. 5.00 g
Question 2
A 50.0 mL sample of a 0.100 M solution of Fe2+ is mixed with 50.0 mL of a 0.100 M solution of MnO4-. What is the resulting concentration of Fe3+?
A. 0.0500 M
B. 0.0750 M
C. 0.100 M
D. 0.125 M
Question 3
The diagram below shows the structure of a molecule. What is the type of bond between atoms A and B?
A. Sigma (σ) bond
B. Pi (π) bond
C. Sigma (σ) and Pi (π) bond
D. Hydrogen bond
Question 4
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. The pH of the resulting solution is 7.00. What is the number of moles of NaOH added?
A. 0.0025 mol
B. 0.0050 mol
C. 0.0075 mol
D. 0.0100 mol
Question 5
A 2.50 g sample of a polymer is dissolved in 100.0 mL of a solvent. The resulting solution has a vis\cosity of 1.25 cP. What is the molar mass of the polymer?
A. 5000 g/mol
B. 10000 g/mol
C. 15000 g/mol
D. 20000 g/mol
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of C(s) + O2(g) → CO2(g).
A. 0 kJ/mol
B. -393.5 kJ/mol
C. 393.5 kJ/mol
D. 0 kJ/mol
Question 7
A 1.00 M solution of HCl is titrated with a 1.00 M solution of NaOH. What is the pH of the solution after 30.0 mL of NaOH has been added?
A. \( pH = \frac{1}{2} \( pH_1 + pH_2 \ \) )
B. \( pH = \frac{1}{2} \( pOH_1 + pOH_2 \ \) )
C. \( pH = \frac{1}{2} \( pH_1 - pH_2 \ \) )
D. \( pH = \frac{1}{2} \( pOH_1 - pOH_2 \ \) )
Question 8
A 2.0 M solution of potassium nitrate (KNO3) is prepared by dissolving 20 g of KNO3 in water to make 100 mL of solution. What is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 9
The diagram below shows the structure of a molecule. What is the type of bond between atoms A and B?
A. Sigma (σ) bond
B. Pi (π) bond
C. Sigma (σ) and Pi (π) bond
D. Hydrogen bond
Question 10
Determine the s\tandard enthalpy of formation of CH3OH(l) from the following data: ΔHf(CO2(g)) = -393.5 kJ/mol, ΔHf(H2O(l)) = -285.8 kJ/mol, ΔHf(CH4(g)) = -74.8 kJ/mol, ΔHf(O2(g)) = 0 kJ/mol.
A. -238.7 kJ/mol
B. -285.8 kJ/mol
C. -393.5 kJ/mol
D. -74.8 kJ/mol
Question 11
The reaction between H2S and O2 is catalyzed by a platinum catalyst. The rate law for the reaction is given by: rate = k[H2S][O2]^2. If the initial concentrations of H2S and O2 are 0.100 M and 0.0500 M, respectively, and the rate of reaction is 0.0100 M/s, what is the value of the rate cons\tant (k)?
A. \( k = \frac{rate}{[H2S][O2]^2} \)
B. \( k = \frac{[H2S][O2]^2}{rate} \)
C. \( k = \frac{rate}{[H2S]^2[O2]} \)
D. \( k = \frac{[H2S]^2[O2]}{rate} \)
Question 12
In a reaction between zinc metal and copper(II) sulfate solution, 25.0 cm³ of 0.100 M zinc sulfate solution is required to react with 25.0 cm³ of 0.100 M copper(II) sulfate solution. Calculate the number of moles of copper(II) ions that reacted.
A. 0.00125 mol
B. 0.0025 mol
C. 0.005 mol
D. 0.0125 mol
Question 13
A 2.5 L flask contains 0.5 mol of an ideal gas at 298 K. Calculate the work done by the gas when it expands to 5 L at cons\tant temperature.
A. 10 J
B. 20 J
C. 30 J
D. 40 J
Question 14
A 1.00 M solution of HCl is titrated with a 1.00 M solution of NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?
A. \( pH = \frac{1}{2} \( pH_1 + pH_2 \ \) )
B. \( pH = \frac{1}{2} \( pOH_1 + pOH_2 \ \) )
C. \( pH = \frac{1}{2} \( pH_1 - pH_2 \ \) )
D. \( pH = \frac{1}{2} \( pOH_1 - pOH_2 \ \) )
Question 15
The reaction between chlorine gas and sodium iodide is represented by the equation: 2NaI(s) + Cl2(g) → 2NaCl(s) + I2(s). What is the oxidation state of iodine in the product I2(s)?
A. 0
B. -1
C. 1
D. 2

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