POST UTME MADONNA UNIVERSITY 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy of formation of NH3(g) is -45.9 kJ/mol. Calculate the s\tandard enthalpy of formation of N2H4(l) from the following data: ΔHf(N2(g)) = 0 kJ/mol, ΔHf(H2(g)) = 0 kJ/mol.
A. -85.8 kJ/mol
B. -85.8 kJ/mol
C. -85.8 kJ/mol
D. -85.8 kJ/mol
Question 2
A solution of NaCl is prepared by dissolving 10 g of NaCl in 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 3
A diagram of a cell is shown below. If the concentration of the H+ ions is 0.100 M, what is the concentration of the OH- ions?
A. 0.100 M
B. 0.0100 M
C. 0.00100 M
D. 0.000100 M
Question 4
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 5
A 1 M solution of a strong acid HA is titrated with 1 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, calculate the pH of the solution at the equivalence point.
A. 1
B. 2
C. 3
D. 4
Question 6
A 2.50 g sample of an unknown metal carbonate is heated to produce 1.25 g of CO2(g). Calculate the molar mass of the metal carbonate.
A. 100.0 g/mol
B. 100.0 g/mol
C. 100.0 g/mol
D. 100.0 g/mol
Question 7
A 5.00 g sample of an unknown metal is heated in air to produce 2.50 g of metal oxide. Calculate the percentage of metal in the original sample.
A. 50.0%
B. 50.0%
C. 50.0%
D. 50.0%
Question 8
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of H2O(g)?
A. -241.8 kJ/mol
B. -393.5 kJ/mol
C. -285.8 kJ/mol
D. -241.8 kJ/mol
Question 9
A sample of a hydrocarbon has a molecular formula of C5H12. What is the type of hydrocarbon and draw its structural formula?
A. Alkane
B. Alkene
C. Alkyne
D. Aromatic hydrocarbon
Question 10
A 0.1 M solution of FeCl3 is electrolyzed u\sing a platinum electrode. What is the mass of Fe deposited at the cathode after 2 hours?
A. 0.1 g
B. 0.2 g
C. 0.3 g
D. 0.4 g
Question 11
The diagram below shows a titration curve. Identify the pH at point X.
A. 2
B. 3
C. 4
D. 5
Question 12
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 13
A 2 M solution of a salt is prepared by dissolving 40 g of the salt in water. What is the molar mass of the salt?
A. 100 g/mol
B. 200 g/mol
C. 300 g/mol
D. 400 g/mol
Question 14
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, calculate the number of moles of HA present in 1 L of the solution.
A. 0.01 mol
B. 0.02 mol
C. 0.03 mol
D. 0.04 mol
Question 15
A gas has a pressure of 2 atm at a temperature of 300 K. What is the pressure of the gas at a temperature of 400 K, assuming the volume remains cons\tant?
A. 1 atm
B. 2 atm
C. 3 atm
D. 4 atm

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