POST UTME CRAWFORD UNIVERSITY 2023 Chemistry | Objective

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Question 1
A solution of sodium chloride is prepared by dissolving 35.5 g of sodium chloride in 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 2
A 0.5 M solution of a weak acid is titrated with 0.5 M NaOH. The pH of the solution at the equivalence point is 7. What is the pKa of the acid?
A. 1
B. 2
C. 3
D. 4
Question 3
The reaction between sodium hydroxide and acetic acid is represented by the equation: CH3COOH + NaOH → CH3COONa + H2O. What is the mole ratio of acetic acid to sodium hydroxide?
A. 1:1
B. 1:2
C. 2:1
D. 3:1
Question 4
A 2.5 g sample of an organic compound containing only carbon and hydrogen is combusted in a bomb calorimeter. The heat of combustion is 12.5 kJ/g. What is the empirical formula of the compound?
A. CH2
B. C2H4
C. C3H6
D. C4H8
Question 5
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) + C(s).
A. -241.8 kJ/mol
B. -285.8 kJ/mol
C. -393.5 kJ/mol
D. -418.8 kJ/mol
Question 6
A solution of sodium chloride is prepared by dissolving 35.5 g of sodium chloride in 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 7
A 2.00 g sample of a non-metallic oxide is heated in a stream of carbon monoxide gas. The resulting gas is collected and found to have a volume of 2.00 L at 25°C and 1.00 atm. What is the empirical formula of the oxide?
A. CO
B. CO2
C. C2O2
D. C3O3
Question 8
A 2.50-g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The amount of CO2 produced is 1.25 g, and the amount of H2O produced is 0.75 g. What is the empirical formula of the compound?
A. CH2
B. C2H4
C. C2H6
D. C3H8
Question 9
A 10.0-mL sample of a solution containing 0.500 M HCl is titrated with 0.500 M NaOH. What is the pH of the solution after the titration is complete?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 10
A 1.00 g sample of a biomolecule is analyzed u\sing a spectrophotometer. The resulting spectrum shows a peak at 260 nm. What is the concentration of the biomolecule?
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 11
A 1.00 M solution of H2SO4 is mixed with a 1.00 M solution of NaOH. Calculate the concentration of the resulting solution.
A. 0.50 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 12
A 2.5 g sample of a non-metallic oxide of nitrogen is heated in a stream of hydrogen gas at 1273 K. The resulting gas is passed through a solution of sodium hydroxide, and the volume of the gas collected at room temperature and pressure is 2.5 liters. What is the empirical formula of the oxide?
A. N2O
B. NO
C. N2O3
D. N2O5
Question 13
A 0.100 M solution of AgNO3 is mixed with a 0.100 M solution of NaCl. Calculate the concentration of AgCl(s) that precipitates.
A. 0.0100 M
B. 0.0200 M
C. 0.0300 M
D. 0.0400 M
Question 14
A solution of 0.100 M NaCl is electrolyzed u\sing a platinum electrode. The electrolysis is carried out at a cons\tant current of 0.500 A for 10.0 min. What is the mass of Cl2 gas collected at the anode?
A. 0.100 g
B. 0.200 g
C. 0.300 g
D. 0.400 g
Question 15
The reaction between hydrogen peroxide (H2O2) and potassium iodide (KI) is a first-order reaction with respect to H2O2. If the initial concentration of H2O2 is 0.1 M and the rate cons\tant (k) is 0.05 min^-1, what is the concentration of H2O2 after 10 minutes?
A. 0.01 M
B. 0.02 M
C. 0.03 M
D. 0.04 M

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