POST UTME MOUNTAIN TOP UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1.00 M solution of a strong acid is mixed with 100.0 mL of a 0.100 M solution of a weak base. If the resulting solution has a pH of 4.00, what is the concentration of the weak base?
A. 0.0100 M
B. 0.100 M
C. 1.00 M
D. 10.0 M
Question 2
A polymer has a molecular weight of 50000 g/mol and a degree of polymerization of 1000. What is the molar mass of the repeating unit?
A. 50 g/mol
B. 500 g/mol
C. 5000 g/mol
D. 50000 g/mol
Question 3
A 0.1 M solution of a weak acid HA is mixed with a 0.1 M solution of a strong base NaOH. If the initial pH of the acid solution is 3.5, what is the pH of the resulting solution after the reaction is complete?
A. 4.5
B. 5.5
C. 6.5
D. 7.5
Question 4
A sample of a non-metallic element has a mass of 25.0 g and a volume of 5.00 cm³. If the density of the element is 2.50 g/cm³, what is the molar mass of the element?
A. 50 g/mol
B. 100 g/mol
C. 150 g/mol
D. 200 g/mol
Question 5
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M HCl. What is the concentration of NaOH after the addition of 25.0 mL of 0.100 M HCl?
A. 0.050 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 6
A 2.00 L flask contains 0.100 mol of a non-ideal gas at 298 K. The gas is heated to 373 K and the volume is increased to 3.00 L. What is the new pressure of the gas?
A. 1.00 atm
B. 2.00 atm
C. 3.00 atm
D. 4.00 atm
Question 7
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the resulting solution after 25.0 mL of NaOH has been added.
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 8
A reaction is carried out at cons\tant pressure, and the temperature is increased from 25°C to 50°C. If the initial volume of the reaction mixture is 2.5 L, and the final volume is 3.2 L, what is the change in entropy (ΔS) of the reaction?
A. 10 J/K
B. 20 J/K
C. 30 J/K
D. 40 J/K
Question 9
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the concentration of HCl after the addition of 50.0 mL of 0.100 M NaOH?
A. 0.050 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 10
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CO(g) from the following reaction: CO2(g) → CO(g) + 1/2O2(g).
A. -110.5 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 11
A solution of NaCl is prepared by dissolving 10 g of NaCl in 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 12
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution?
A. 0
B. 1
C. 7
D. 14
Question 13
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 12.5 mL
B. 25.0 mL
C. 37.5 mL
D. 50.0 mL
Question 14
A solution contains 10% ethanol by volume. If 100 mL of the solution is diluted to 200 mL, what is the concentration of ethanol in the new solution?
A. 5%
B. 10%
C. 15%
D. 20%
Question 15
A 0.1 M solution of a weak base B is mixed with a 0.1 M solution of a strong acid HCl. If the initial pH of the base solution is 10.5, what is the pH of the resulting solution after the reaction is complete?
A. 5.5
B. 6.5
C. 7.5
D. 8.5

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