POST UTME EKSU 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
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 2
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 3
What is the molar mass of H2O?
A. 18 g/mol
B. 18.01 g/mol
C. 18.02 g/mol
D. 18.03 g/mol
Question 4
The atomic radius of a certain element is 0.125 nm. If the element has a crystal structure with a lattice parameter of 0.500 nm, calculate the density of the element.
A. 2.50 g/cm³
B. 2.55 g/cm³
C. 2.60 g/cm³
D. 2.65 g/cm³
Question 5
The reaction of sodium hydroxide with hydrochloric acid produces a gas that is released into the atmosphere. What is the name of this gas?
A. Carbon dioxide
B. Nitrogen
C. Hydrogen chloride
D. Water vapor
Question 6
A sample of an ideal gas is heated from 300 K to 400 K at cons\tant volume. Calculate the change in entropy (ΔS) of the gas, given that the molar heat capacity at cons\tant volume (Cv) is 20.8 J/mol·K.
A. 10.3 J/K
B. 20.6 J/K
C. 30.9 J/K
D. 41.2 J/K
Question 7
A solution of 0.1 M H2SO4 is mixed with a solution of 0.1 M NaOH. The reaction is as follows: H2SO4 + 2NaOH → Na2SO4 + 2H2O. If the initial volume of the H2SO4 solution is 100 mL and the initial volume of the NaOH solution is 50 mL, what is the concentration of Na2SO4 formed after the reaction is complete?
A. 0.033 M
B. 0.066 M
C. 0.1 M
D. 0.133 M
Question 8
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 9
A 2.00 M solution of HCl is titrated with a 1.00 M solution of NaOH. If 25.0 mL of NaOH is required to reach the equivalence point, what is the volume of HCl used?
A. 50.0 mL
B. 25.0 mL
C. 12.5 mL
D. 6.25 mL
Question 10
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 11
A 2.5 M solution of sodium hydroxide (NaOH) is mixed with a 2.5 M solution of hydrochloric acid (HCl). What is the pH of the resulting solution?
A. 1
B. 7
C. 10
D. 14
Question 12
The diagram below shows a gas collection apparatus. What is the purpose of the gas syringe?
A. To measure the volume of the gas
B. To measure the pressure of the gas
C. To measure the temperature of the gas
D. To measure the density of the gas
Question 13
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 14
The s\tandard enthalpy of formation (ΔHf) of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of C6H12O6(s) to form CO2(g) and H2O(l).
A. -2803.0 kJ/mol
B. -2803.5 kJ/mol
C. -2804.0 kJ/mol
D. -2804.5 kJ/mol
Question 15
What is the molar mass of NH3?
A. 17 g/mol
B. 17.01 g/mol
C. 17.02 g/mol
D. 17.03 g/mol

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