POST UTME EKSU 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the repeating unit.
A. 100 g/mol
B. 200 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 2
A 2.0 L solution of 0.5 M CH3CH2OH is mixed with a 1.0 L solution of 0.2 M HCl. What is the concentration of CH3CH2OH in the resulting solution?
A. 0.25 M
B. 0.3 M
C. 0.35 M
D. 0.4 M
Question 3
The rate cons\tant (k) of a first-order reaction is given by the equation: k = 2.303/t \log10\( A0/A \). If the initial concentration of a reac\tant is 0.1 M and the concentration after 10 minutes is 0.05 M, calculate the rate cons\tant (k) in min^-1.
A. 0.0005 min^-1
B. 0.001 min^-1
C. 0.005 min^-1
D. 0.01 min^-1
Question 4
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -393.5 kJ/mol
C. -74.8 kJ/mol
D. -283.5 kJ/mol
Question 5
A 1.00 L sample of 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the pH of the solution at the equivalence point.
A. 7.00
B. 8.00
C. 9.00
D. 10.0
Question 6
The reaction of cyclohexane with bromine in the presence of light produces a mixture of 1,2-dibromocyclohexane and 1,4-dibromocyclohexane. What is the major product of this reaction?
A. 1,2-dibromocyclohexane
B. 1,4-dibromocyclohexane
C. cis-1,2-dibromocyclohexane
D. trans-1,2-dibromocyclohexane
Question 7
A 1.00 M solution of H2SO4(aq) is mixed with a 1.00 M solution of NaOH(aq) in a 1.00 L flask. What is the concentration of the resulting solution?
A. 0.500 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 8
A diagram of the apparatus used to determine the molar mass of a gas is shown below. What is the purpose of the U-tube manometer?
A. to measure the pressure of the gas
B. to measure the volume of the gas
C. to measure the temperature of the gas
D. to measure the molar mass of the gas
Question 9
A diagram of a gas apparatus is shown below.
A. The flask contains the gas.
B. The tube contains the gas.
C. The flask contains the liquid.
D. The tube contains the liquid.
Question 10
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C6H12O6(s).
A. -2800 kJ
B. -2900 kJ
C. -3000 kJ
D. -3100 kJ
Question 11
A solution of 0.1 M HCl is titrated with a solution of 0.1 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, what is the volume of HCl required to reach the equivalence point?
A. 20 mL
B. 30 mL
C. 40 mL
D. 50 mL
Question 12
The half-life of a radioactive subs\tance is 10 years. If the initial activity is 100 Bq, what is the activity after 20 years?
A. 25 Bq
B. 50 Bq
C. 75 Bq
D. 100 Bq
Question 13
Determine the molar solubility of BaSO4 in 0.1 M Na2SO4 solution, given that the solubility product cons\tant (Ksp) for BaSO4 is 1.1 x 10^-10.
A. 1.0 x 10^-5 M
B. 1.0 x 10^-6 M
C. 1.0 x 10^-7 M
D. 1.0 x 10^-8 M
Question 14
A 2.5 g sample of a non-metallic oxide is dissolved in 50 cm³ of water. If the resulting solution has a pH of 3.5, what is the molar mass of the oxide?
A. 100 g/mol
B. 200 g/mol
C. 300 g/mol
D. 400 g/mol
Question 15
A sample of nitrogen gas is collected over water at 25.0°C and 1.00 atm. What is the partial pressure of the nitrogen gas?
A. 0.950 atm
B. 0.975 atm
C. 1.00 atm
D. 1.05 atm

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