POST UTME EKSU 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The enthalpy change for the reaction 2NO(g) → N2(g) + O2(g) is -179.6 kJ/mol. What is the s\tandard enthalpy of formation of NO(g)?
A. -90.8 kJ/mol
B. -179.6 kJ/mol
C. 90.8 kJ/mol
D. 179.6 kJ/mol
Question 2
At 273 K, 1.00 L of an ideal gas at 1.00 atm occupies a volume of 22.4 L. What is the volume occupied by 2.00 moles of the same gas at 1.00 atm and 273 K?
A. 44.8 L
B. 22.4 L
C. 11.2 L
D. 5.6 L
Question 3
A mixture of 0.500 g of NaOH and 0.500 g of HCl was dissolved in 1.00 L of water. Calculate the concentration of the resulting solution in units of M.
A. 0.500 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 4
A diagram of a redox reaction is shown below. What is the oxidation state of the manganese ion in the compound MnO2?
A. +2
B. +4
C. +6
D. +8
Question 5
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. What is the molar mass of the repeating unit?
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 6
What is the pH of a solution that is 0.01 M in H2SO4?
A. 0
B. 1
C. 2
D. 3
Question 7
A 10.0 g sample of a polymer is dissolved in 100.0 mL of solvent. If the polymer has a molecular weight of 50,000 g/mol, calculate the number of polymer molecules in the solution.
A. 1.00 x 10^20
B. 1.00 x 10^22
C. 1.00 x 10^24
D. 1.00 x 10^26
Question 8
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the repeating unit.
A. 200 g/mol
B. 250 g/mol
C. 300 g/mol
D. 350 g/mol
Question 9
A sample of a non-metallic element has a mass of 2.5 g and a volume of 1.5 cm3. What is the density of the element?
A. 1.5 g/cm3
B. 1.67 g/cm3
C. 2.0 g/cm3
D. 2.5 g/cm3
Question 10
A 0.500 L sample of a solution containing 0.100 M HCl was titrated with 0.100 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 0.500 L
B. 0.750 L
C. 1.00 L
D. 1.25 L
Question 11
The half-life of a radioactive subs\tance is 5.00 days. Calculate the activity of a 1.00 g sample after 20.0 days.
A. 2.50 × 10^-3 Bq
B. 5.00 × 10^-3 Bq
C. 1.00 × 10^-2 Bq
D. 2.50 × 10^-2 Bq
Question 12
A diagram of a titration setup is shown below. What is the purpose of the burette in this setup?
A. To measure the volume of the acid
B. To measure the volume of the base
C. To mix the acid and base
D. To measure the pH of the solution
Question 13
Determine the number of moles of oxygen gas (O2) produced at STP when 2.5 moles of potassium chlorate (KClO3) decompose according to the equation: 2KClO3(s) → 2KCl(s) + 3O2(g).
A. 1.5 moles
B. 2.5 moles
C. 3.75 moles
D. 5 moles
Question 14
A 1.00 L solution contains 0.100 mol of NaCl. What is the concentration of the solution in g/L?
A. 10.0 g/L
B. 20.0 g/L
C. 30.0 g/L
D. 40.0 g/L
Question 15
The rate cons\tant for the reaction 2NO + O2 → 2NO2 is 0.0500 s^-1 at 298 K. Calculate the rate of reaction when [NO] = 0.100 M and [O2] = 0.0500 M.
A. 2.50 × 10^-3 M s^-1
B. 5.00 × 10^-3 M s^-1
C. 1.00 × 10^-2 M s^-1
D. 2.00 × 10^-2 M s^-1

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