POST UTME UNIOSUN 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 10 mL sample of a 0.1 M solution of NaOH is titrated with a 0.1 M solution of HCl. Calculate the pH of the solution after the titration.
A. 1
B. 2
C. 3
D. 4
Question 2
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. The solution is then titrated with a 0.1 M NaOH solution. If the equivalence point is reached at 25 mL, what is the molar mass of the polymer?
A. 500 g/mol
B. 600 g/mol
C. 700 g/mol
D. 800 g/mol
Question 3
A 2.00 g sample of an unknown hydrocarbon is burned in a bomb calorimeter. If the heat of combustion is 42.0 kJ/g, what is the molar mass of the hydrocarbon?
A. 50.0 g/mol
B. 60.0 g/mol
C. 70.0 g/mol
D. 80.0 g/mol
Question 4
A 10.0 g sample of a metal is heated in a crucible until it melts. The mass of the crucible and metal is 10.5 g. The mass of the crucible alone is 5.00 g. What is the mass of the metal?
A. 5.00 g
B. 7.50 g
C. 10.0 g
D. 12.5 g
Question 5
Determine the type of hybridization exhibited by the central atom in the molecule CH2Cl2.
A. sp3
B. sp2
C. sp
D. dsp3
Question 6
The s\tandard electrode potential (E°) of the Zn^2+/Zn couple is -0.76 V. What is the s\tandard electrode potential (E°) of the Cu^2+/Cu couple if the s\tandard electrode potential (E°) of the Cu^2+/Cu couple is 0.34 V?
A. -0.42 V
B. -0.76 V
C. 0.34 V
D. 0.76 V
Question 7
A solution containing 0.250 mol of NaCl is diluted to a total volume of 1.50 L. Calculate the resulting concentration of NaCl.
A. 0.167 M
B. 0.167 M
C. 0.250 M
D. 0.500 M
Question 8
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. If the pH of the resulting solution is 7.00, what is the volume of NaOH added?
A. 12.5 mL
B. 25.0 mL
C. 37.5 mL
D. 50.0 mL
Question 9
The reaction of 2.00 g of an unknown hydrocarbon with 50.0 mL of 1.00 M HCl produces 1.00 g of CO2 and 1.00 g of H2O. What is the empirical formula of the hydrocarbon?
A. C2H4
B. C3H6
C. C4H8
D. C5H10
Question 10
A solution of a salt, Na2SO4, is prepared by dissolving 10 g of the salt in 100 mL of water. The resulting solution has a concentration of 0.1 M. What is the molar mass of the salt?
A. 142 g/mol
B. 150 g/mol
C. 160 g/mol
D. 170 g/mol
Question 11
A 2.00 g sample of an unknown nonmetal is burned in a bomb calorimeter. If the heat of combustion is 35.0 kJ/g, what is the molar mass of the nonmetal?
A. 40.0 g/mol
B. 50.0 g/mol
C. 60.0 g/mol
D. 70.0 g/mol
Question 12
A 0.500 M solution of NaCl is prepared by dissolving 2.50 g of NaCl in 1.00 L of water. What is the concentration of Cl- ions in the solution?
A. 0.250 M
B. 0.500 M
C. 0.750 M
D. 1.00 M
Question 13
A 1.00 M solution of HCl is mixed with a 1.00 M solution of NaOH. If the resulting solution is 0.500 M HCl, what is the initial volume of the HCl solution?
A. 1.00 L
B. 2.00 L
C. 3.00 L
D. 4.00 L
Question 14
The reaction of a hydrocarbon, C6H14, with oxygen gas (O2) in the presence of a catalyst produces carbon dioxide and water. What is the balanced equation for the reaction?
A. C6H14 + 9O2 → 6CO2 + 7H2O
B. C6H14 + 8O2 → 6CO2 + 6H2O
C. C6H14 + 7O2 → 6CO2 + 5H2O
D. C6H14 + 6O2 → 6CO2 + 4H2O
Question 15
A 10 mL sample of a 0.1 M solution of NaOH is titrated with a 0.1 M solution of HCl. What is the volume (in mL) of HCl required to reach the equivalence point?
A. 10 mL
B. 20 mL
C. 30 mL
D. 40 mL

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