POST UTME ESUT 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A solution of sodium chloride (NaCl) is prepared by dissolving 35.5 g of NaCl in 100 mL of water. Calculate the molar concentration of the solution. The molar mass of NaCl is 58.44 g/mol.
A. 0.61 M
B. 0.61 g/mol
C. 0.61 L
D. 0.61 g
Question 2
The solubility of a subs\tance is defined as the maximum amount of the subs\tance that can dissolve in a given amount of solvent at a particular temperature. What is the term for the minimum amount of a subs\tance required to dissolve in a given amount of solvent at a particular temperature?
A. Saturated solution
B. Solubility limit
C. Critical concentration
D. Minimum solubility
Question 3
The rate of a chemical reaction is influenced by several factors, including the concentration of reac\tants, temperature, and surface area. What is the term for the minimum amount of energy required for a reaction to occur?
A. Activation energy
B. Reaction energy
C. Thermal energy
D. Kinetic energy
Question 4
A 2.0 L flask contains 0.5 mol of an ideal gas at 25°C. Calculate the work done by the gas when it expands from 1.0 L to 2.0 L at cons\tant pressure.
A. 2.5 J
B. 5.0 J
C. 7.5 J
D. 10 J
Question 5
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 6
A diagram of a gas collection apparatus is shown below. If 250 mL of gas is collected at a pressure of 750 mmHg and a temperature of 25°C, what is the volume of the gas at STP?
A. 1.0 L
B. 1.5 L
C. 2.0 L
D. 2.5 L
Question 7
A sample of a non-metallic oxide, X2O3, has a molar mass of 144 g/mol. If the oxide is 80% oxygen by mass, what is the molar mass of element X?
A. 72 g/mol
B. 80 g/mol
C. 96 g/mol
D. 112 g/mol
Question 8
A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 9
A solution containing 0.1 M Fe2+ ions is mixed with a solution containing 0.1 M SCN- ions. Calculate the concentration of the complex ion [Fe(SCN)6]4- formed after the reaction is complete.
A. \( K = \frac{[Fe\( SCN \ \)_6]^{4-}}{[Fe^{2+}] [SCN^-]^6} )
B. \( K = \frac{[Fe\( SCN \ \)_6]^{4-}}{[Fe^{2+}] [SCN^-]^3} )
C. \( K = \frac{[Fe\( SCN \ \)_6]^{4-}}{[Fe^{2+}] [SCN^-]^2} )
D. \( K = \frac{[Fe\( SCN \ \)_6]^{4-}}{[Fe^{2+}] [SCN^-]^5} )
Question 10
A reaction is represented by the equation: 2A + B → 2C + D. If the rate cons\tant (k) is 0.05 min^-1 and the initial concentrations of A and B are 0.1 M and 0.2 M, respectively, what is the rate of reaction after 10 minutes?
A. 0.001 M/min
B. 0.01 M/min
C. 0.1 M/min
D. 1 M/min
Question 11
The reaction between nitrogen and oxygen to form nitrogen dioxide is a classic example of a redox reaction. What is the oxidation state of nitrogen in the product?
A. +2
B. +4
C. +6
D. +8
Question 12
Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g), given that the initial concentrations of NO and O2 are 0.5 M and 0.2 M, respectively, and the rate of reaction is 0.02 M/s after 10 minutes.
A. \( k = \frac{2.303}{t} \log \frac{[NO]_0 [O_2]_0}{[NO_2]_t} \)
B. \( k = \frac{2.303}{t} \log \frac{[NO_2]_t}{[NO]_0 [O_2]_0} \)
C. \( k = \frac{2.303}{t} \log \frac{[NO]_0 [O_2]_0}{[NO_2]_t} \)
D. \( k = \frac{2.303}{t} \log \frac{[NO_2]_t}{[NO]_0 [O_2]_0} \)
Question 13
A 1.0 L flask contains 0.5 mol of a non-ideal gas at 25°C. Calculate the pressure of the gas u\sing the van der Waals equation.
A. 1.01 x 10^5 Pa
B. 2.02 x 10^5 Pa
C. 3.03 x 10^5 Pa
D. 4.04 x 10^5 Pa
Question 14
A metal has a density of 8 g/cm^3 and a volume of 10 cm^3. Calculate the mass of the metal.
A. 80 g
B. 100 g
C. 120 g
D. 140 g
Question 15
A solution of H2SO4 is electrolyzed u\sing a platinum electrode. If the current is 5 A and the time is 10 min, what is the mass of H2 gas produced?
A. 0.5 g
B. 1 g
C. 1.5 g
D. 2 g

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: