POST UTME COVENANT UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1.5 M solution of potassium hydroxide is mixed with a 1.5 M solution of sulfuric acid. What is the resulting concentration of the solution?
A. 1.5 M
B. 3 M
C. 6 M
D. 0 M
Question 2
A sample of CO2 is collected over water at a temperature of 25°C and a pressure of 1 atm. If the partial pressure of CO2 is 0.5 atm, what is the mole \fraction of CO2 in the gas mixture?
A. \( x_{CO_2} = \frac{P_{CO_2}}{P_{total}} \)
B. \( x_{CO_2} = \frac{P_{total}}{P_{CO_2}} \)
C. \( x_{CO_2} = \frac{V_{CO_2}}{V_{total}} \)
D. \( x_{CO_2} = \frac{V_{total}}{V_{CO_2}} \)
Question 3
Determine the number of moles of carbon dioxide produced when 2.5 liters of carbon monoxide at 27°C and 1 atm is passed over heated copper(II) oxide.
A. 0.25 mol
B. 0.5 mol
C. 1 mol
D. 1.25 mol
Question 4
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of H2(g)?
A. 0 kJ/mol
B. -285.8 kJ/mol
C. -110.5 kJ/mol
D. -393.5 kJ/mol
Question 5
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.60 kJ/mol
C. -1206.60 kJ/mol
D. -1206.60 kJ/mol
Question 6
A 2.50 g sample of a polymer is dissolved in 100 mL of a solvent. If the polymer has a molecular weight of 50,000 g/mol, what is the concentration of the polymer solution in g/L?
A. 0.050 g/L
B. 0.050 g/L
C. 0.050 g/L
D. 0.050 g/L
Question 7
The energy of an electron in the nth orbit of a hydrogen atom is given by the equation \( E_n = -\frac{13.6}{n^2} \) eV. If the energy of an electron in the 3rd orbit is -1.51 eV, what is the energy of an electron in the 4th orbit?
A. -0.85
B. -1.51
C. -2.17
D. -3.40
Question 8
A gas is confined to a container with a volume of 2.5 L. If the temperature is increased from 20°C to 50°C, what is the new volume of the gas?
A. 3.2 L
B. 3.5 L
C. 3.8 L
D. 4.0 L
Question 9
A 2.5 M solution of sodium hydroxide is mixed with a 2.5 M solution of hydrochloric acid. What is the resulting concentration of the solution?
A. 2.5 M
B. 5 M
C. 10 M
D. 0 M
Question 10
A sample of a polymer has a molecular weight of 50000 g/mol. If the polymer has a degree of polymerization of 200, what is the molecular weight of the repeating unit?
A. 250
B. 500
C. 750
D. 1000
Question 11
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. -283.0 kJ/mol
Question 12
A diagram of a gas collection setup is shown below. What is the purpose of the gas syringe in this setup?
A. To measure the volume of the gas
B. To measure the pressure of the gas
C. To mix the gases
D. To filter the gas
Question 13
A 25.0 cm3 sample of 0.100 M HCl is titrated with 0.150 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 50.0 cm3
B. 75.0 cm3
C. 100 cm3
D. 125 cm3
Question 14
A 0.500 M solution of NaOH is mixed with a 0.500 M solution of HCl. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 15
A 2.0 g sample of a compound containing only carbon and oxygen is analyzed by combustion. The volume of CO2 produced is 1.5 L at 298 K and 1 atm. The volume of H2O produced is 0.5 L at 298 K and 1 atm. Calculate the empirical formula of the compound.
A. CO
B. C2O2
C. C3O3
D. C4O4

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