POST UTME NOUN 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A diagram of a chromatography setup is shown below. What is the purpose of the stationary phase in this setup?
A. To separate the components of the mixture
B. To identify the components of the mixture
C. To measure the concentration of the mixture
D. To separate the solvent from the solute
Question 2
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/\( mol*K \), and the temperature (T) is 300 K, what is the value of the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^\( -1 \)?
A. 1.0 x 10^\( -10 \) s^\( -1 \)
B. 1.0 x 10^\( -9 \) s^\( -1 \)
C. 1.0 x 10^\( -8 \) s^\( -1 \)
D. 1.0 x 10^\( -7 \) s^\( -1 \)
Question 3
A 2 M solution of a weak acid is titrated with 2 M NaOH. If 10 mL of the acid is required to reach the equivalence point, what is the pH of the solution at the equivalence point?
A. 7
B. 9
C. 11
D. 13
Question 4
Determine the number of moles of oxygen gas (O2) required to completely combust 2.50 moles of propane (C3H8) according to the balanced equation: C3H8 + 5O2 → 3CO2 + 4H2O.
A. 1.25 moles
B. 2.50 moles
C. 3.75 moles
D. 5.00 moles
Question 5
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. 0.5 M
C. 1.0 M
D. 2.0 M
Question 6
A sample of a polymer is analyzed by gel permeation chromatography (GPC). The chromatogram shows a \single peak with a retention time of 10 minutes. What is the molecular weight of the polymer?
A. 1000 g/mol
B. 10000 g/mol
C. 100000 g/mol
D. 1000000 g/mol
Question 7
A gas at s\tandard temperature and pressure (STP) has a volume of 22.4 L. What is the number of moles of the gas?
A. 1.00 mol
B. 2.00 mol
C. 3.00 mol
D. 4.00 mol
Question 8
A solution of sulfuric acid is prepared by dissolving 25 g of sulfuric acid in 100 mL of water. What is the concentration of the solution in terms of molarity?
A. 0.5 M
B. 1.0 M
C. 2.0 M
D. 5.0 M
Question 9
A solution contains 2.50 g of sodium chloride (NaCl) dissolved in 100.0 mL of water. What is the molarity of the solution?
A. 0.0500 M
B. 0.100 M
C. 0.200 M
D. 0.500 M
Question 10
A sample of nitrogen gas is collected over water at a temperature of 25°C and a pressure of 1 atm. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of nitrogen gas?
A. 760 mmHg
B. 737 mmHg
C. 714 mmHg
D. 691 mmHg
Question 11
A solution of 0.1 M NaOH is titrated with 0.1 M HCl. What is the pH of the solution after 25 mL of HCl has been added to 25 mL of NaOH?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 12
A sample of a non-metallic element has a mass of 25.0 g and a density of 3.50 g/cm3. What is the volume of the sample in cubic centimeters?
A. 5.71 cm3
B. 7.14 cm3
C. 10.0 cm3
D. 14.3 cm3
Question 13
A sample of a polymer is analyzed by size exclusion chromatography (SEC). The chromatogram shows a \single peak with a retention time of 15 minutes. What is the molecular weight of the polymer?
A. 5000 g/mol
B. 10000 g/mol
C. 15000 g/mol
D. 20000 g/mol
Question 14
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. What is the molar mass of the repeating unit?
A. 200 g/mol
B. 400 g/mol
C. 600 g/mol
D. 800 g/mol
Question 15
A solution contains 10.0 g of glu\cose (C6H12O6) dissolved in 100.0 mL of water. What is the concentration of the solution in grams per liter?
A. 10.0 g/L
B. 20.0 g/L
C. 30.0 g/L
D. 40.0 g/L

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