POST UTME NOUN 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. At the equivalence point, the pH of the solution is 7. What is the pKa of the acid?
A. 4.76
B. 5.76
C. 6.76
D. 7.76
Question 2
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution after mixing?
A. 1
B. 2
C. 3
D. 4
Question 3
A sample of nitrogen gas (N2) is collected over water at a temperature of 25°C and a pressure of 1 atm. If the partial pressure of water vapor is 0.03 atm, what is the mole \fraction of nitrogen gas?
A. 0.97
B. 0.98
C. 0.99
D. 1.00
Question 4
A solution of NaCl is prepared by dissolving 35.5 g of NaCl in 250 mL of water. What is the molarity of the solution?
A. 0.20 M
B. 0.30 M
C. 0.40 M
D. 0.50 M
Question 5
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 200. Calculate the molar mass of the repeating unit.
A. 250 g/mol
B. 500 g/mol
C. 750 g/mol
D. 1000 g/mol
Question 6
A 0.1 M solution of a weak acid is titrated with 0.1 M NaOH. At the equivalence point, the pH of the solution is 8. What is the pKa of the acid?
A. 4.76
B. 5.76
C. 6.76
D. 7.76
Question 7
A sample of a polymer has a molecular weight of 50000 g/mol. If the degree of polymerization is 200, what is the molar mass of the repeating unit?
A. 250
B. 500
C. 750
D. 1000
Question 8
The half-life of a radioactive subs\tance is 5.0 days. If 100 mg of the subs\tance is initially present, what is the amount of the subs\tance remaining after 10 days?
A. 25 mg
B. 50 mg
C. 75 mg
D. 100 mg
Question 9
A 1.0 M solution of H2SO4 is titrated with a 1.0 M solution of NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.
A. 2
B. 2
C. 2
D. 2
Question 10
A 2.5 M solution of HCl is titrated with a 1.5 M solution of NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.
A. 2.5
B. 2.5
C. 2.5
D. 2.5
Question 11
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 12
A metal has a density of 8.5 g/cm^3 and a molar mass of 65 g/mol. Calculate the number of moles of metal in 100 g of the metal.
A. 1.5 mol
B. 2.0 mol
C. 2.5 mol
D. 3.0 mol
Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CO(g) if the s\tandard enthalpy of formation of C(s) is 0 kJ/mol and the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol.
A. -110.5 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 14
The following diagram shows a titration setup. Identify the part labeled A.
A. Burette
B. Beaker
C. Test Tube
D. Cylinder
Question 15
A solution contains 2.5 g of sodium chloride (NaCl) dissolved in 100 mL of water. What is the molarity of the solution?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.00 M

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