POST UTME AL-HIKMAH UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard Gibbs free energy change for the reaction 2H2(g) + O2(g) → 2H2O(l) is -237 kJ/mol. Calculate the equilibrium cons\tant (K) for the reaction.
A. 1.0 x 10^10
B. 1.0 x 10^10
C. 1.0 x 10^10
D. 1.0 x 10^10
Question 2
A sample of a polymer has a molecular weight of 50,000 g/mol. If 2.5 g of the polymer is dissolved in 100 mL of solvent, what is the concentration of the solution in g/L?
A. 0.05 g/L
B. 0.5 g/L
C. 5 g/L
D. 50 g/L
Question 3
A 25 mL sample of 0.5 M NaOH is titrated with 0.5 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.025
B. 0.05
C. 0.075
D. 0.1
Question 4
A 0.5 M solution of H2SO4 is mixed with a 0.5 M solution of NaOH. Calculate the pH of the resulting solution.
A. 2.5
B. 2.5
C. 2.5
D. 2.5
Question 5
A 2.0 L flask contains 0.5 mol of N2 at 27°C. Calculate the number of moles of O2 required to react with the N2 to form N2O.
A. 0.25 mol
B. 0.5 mol
C. 0.75 mol
D. 1.0 mol
Question 6
A solution of 10 g of NaCl in 100 g of water has a boiling point elevation of 0.5°C. Calculate the molality of the solution.
A. 0.1 m
B. 0.2 m
C. 0.3 m
D. 0.4 m
Question 7
The s\tandard Gibbs free energy change for the reaction 2NO(g) + O2(g) → 2NO2(g) is -110 kJ/mol. Calculate the equilibrium cons\tant (K) for the reaction.
A. 1.0 x 10^10
B. 1.0 x 10^10
C. 1.0 x 10^10
D. 1.0 x 10^10
Question 8
What is the major product of the reaction between 2-methylpropane and chlorine?
A. \( CH_3CH_2CH_2CH_2Cl \)
B. \( CH_3CH_2CH_2CH_2CH_2Cl \)
C. \( CH_3CH_2CH_2CH_2CH_2CH_2Cl \)
D. \( CH_3CH_2CH_2CH_2CH_2CH_2CH_2Cl \)
Question 9
A diagram of a redox reaction is shown below. What is the oxidation state of the manganese ion in the compound MnO2?
A. +4
B. +2
C. 0
D. -2
Question 10
A diagram of a titration setup is shown below. What is the pH of the solution after the addition of 25 mL of 1 M HCl to 25 mL of 0.1 M NaOH?
A. 7
B. 9
C. 11
D. 13
Question 11
A 10 L \tank contains 5 kg of CO2 at 25°C. What is the concentration of CO2 in the \tank?
A. 0.5 M
B. 0.2 M
C. 0.1 M
D. 0.3 M
Question 12
A solution contains 0.1 M NaCl and 0.2 M CaCl2. What is the concentration of Cl- ions in the solution?
A. 0.3 M
B. 0.2 M
C. 0.1 M
D. 0.4 M
Question 13
A sample of a metal (X) has a density of 11.5 g/cm^3 and a volume of 2.5 cm^3. Calculate the mass of the sample.
A. 28.75 g
B. 28.75 g
C. 28.75 g
D. 28.75 g
Question 14
A 5 L flask contains 0.5 mol of an ideal gas at 25°C. If the gas is compressed to 2 L, what is the new concentration of the gas?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1 M
Question 15
The atomic radius of an element is 100 pm. If the element is in its ground state, what is the expected value of the atomic radius when it is in its first excited state?
A. 120 pm
B. 90 pm
C. 110 pm
D. 130 pm

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