POST UTME UNIOSUN 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
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 2
The half-life of a radioactive subs\tance is 5 years. If the initial activity is 1000 Bq, what is the activity after 10 years?
A. 250 Bq
B. 500 Bq
C. 750 Bq
D. 1000 Bq
Question 3
A 2.5 g sample of a subs\tance is dissolved in 50 mL of water. The resulting solution has a concentration of 0.5 M. What is the molar mass of the subs\tance?
A. 10 g/mol
B. 20 g/mol
C. 30 g/mol
D. 40 g/mol
Question 4
A 2.0 L flask contains a mixture of 1.0 M HCl and 0.5 M NaOH. What is the concentration of the resulting solution?
A. 0.5 M
B. 1 M
C. 1.5 M
D. 2 M
Question 5
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, how much will remain after 15 years?
A. 12.5 g
B. 25 g
C. 50 g
D. 100 g
Question 6
A 2.0 L flask contains 0.50 mol of CO2 at 25°C. Calculate the partial pressure of CO2 u\sing the ideal gas law.
A. 1.1 atm
B. 1.2 atm
C. 1.3 atm
D. 1.4 atm
Question 7
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. What is the s\tandard enthalpy of formation of CO2(g)?
A. -393.5 kJ/mol
B. -283.4 kJ/mol
C. -74.8 kJ/mol
D. -110.5 kJ/mol
Question 8
A 10.0 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. 10.0 mL
B. 20.0 mL
C. 30.0 mL
D. 40.0 mL
Question 9
A 10.0 mL sample of a solution containing 0.1 M CuSO4 is titrated with 0.1 M NaOH. What is the volume of NaOH required to reach the equivalence point?
A. 10 mL
B. 20 mL
C. 30 mL
D. 40 mL
Question 10
The reaction of polyethylene with oxygen in the presence of a catalyst is an example of a
A. combustion reaction
B. oxidation reaction
C. polymerization reaction
D. degradation reaction
Question 11
A 2.5 M solution of HCl is prepared by dissolving 25 g of HCl in 1000 mL of water. Calculate the number of moles of HCl in the solution.
A. 0.1 mol
B. 0.2 mol
C. 0.25 mol
D. 0.5 mol
Question 12
The reaction of iron with oxygen in the presence of moisture is an example of a
A. corrosion reaction
B. oxidation reaction
C. polymerization reaction
D. degradation reaction
Question 13
A 1.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. If the initial concentrations of NaOH and HCl are 0.5 M and 0.5 M, respectively, what is the concentration of NaOH after the reaction is complete?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1.0 M
Question 14
The electrolysis of water produces hydrogen gas at the cathode and oxygen gas at the anode. What is the half-reaction at the cathode?
A. 2H+ + 2e- → H2
B. 2H2O → O2 + 4H+ + 4e-
C. 2H2O + 2e- → H2 + 2OH-
D. 2H+ + 2e- → H2O
Question 15
A 2.5 L flask contains 0.5 mol of an ideal gas at 25°C. What is the pressure of the gas?
A. 1.5 atm
B. 2.5 atm
C. 3.5 atm
D. 4.5 atm

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