POST UTME NILE UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A solution of sodium chloride is electrolyzed u\sing a platinum electrode. The reaction at the cathode is:
A. 2Na+(aq) + 2e- → Na(s)
B. 2Cl-(aq) + 2e- → Cl2(g)
C. 2Na+(aq) + 2e- → Na2(g)
D. 2Cl-(aq) + 2e- → Cl2(s)
Question 2
A diagram of a gas law setup is shown below. If the initial pressure is 1 atm and the final pressure is 2 atm, what is the final volume?
A. 2.5 L
B. 5 L
C. 10 L
D. 20 L
Question 3
A sample of hydrogen gas (H2) is collected over water at a temperature of 25°C and a pressure of 1.00 atm. Calculate the partial pressure of hydrogen gas in the sample.
A. 0.50 atm
B. 0.75 atm
C. 1.00 atm
D. 1.25 atm
Question 4
A sample of a metal (M) reacts with oxygen gas to form a metal oxide (MO). If 2.5 g of the metal is burned in air, and the volume of oxygen gas consumed is 1.2 L at 25°C and 1 atm, calculate the molar mass of the metal.
A. 50 g/mol
B. 60 g/mol
C. 70 g/mol
D. 80 g/mol
Question 5
Determine the s\tandard electrode potential of the cell represented by the following reaction: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O. Given that the s\tandard electrode potential of the MnO4-/Mn2+ couple is +1.23 V.
A. +1.23 V
B. +1.46 V
C. +1.69 V
D. +1.92 V
Question 6
A non-metal is prepared by the reaction of a metal with a non-metal. The reaction is:
A. 2Na + Cl2 → 2NaCl
B. 2Na + S → Na2S
C. 2Na + O2 → Na2O
D. 2Na + N2 → Na2N2
Question 7
A 1.00 M solution of sodium chloride (NaCl) is mixed with a 1.00 M solution of hydrochloric acid (HCl). Calculate the concentration of the resulting solution.
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.00 M
Question 8
A diagram of a titration setup is shown below. If the burette contains 25 mL of 0.1 M sodium hydroxide and the titration requires 15 mL of the base to reach the \endpoint, what is the concentration of the acid?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 9
A diagram of a simple harmonic oscillator is shown below. If the oscillator has a mass of 2.0 kg and a spring cons\tant of 100 N/m, calculate the frequency of oscillation.
A. 1.0 Hz
B. 2.0 Hz
C. 3.0 Hz
D. 4.0 Hz
Question 10
A 2.0 L container is filled with 1.5 mol of an ideal gas at 27°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 2.5 atm
B. 3.0 atm
C. 3.5 atm
D. 4.0 atm
Question 11
A solution contains 0.1 M NaCl. What is the concentration of Cl- ions in the solution?
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 12
The s\tandard enthalpy of formation of carbon dioxide (CO2) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of carbon monoxide (CO) if the s\tandard enthalpy of formation of carbon (C) is -717.1 kJ/mol and the s\tandard enthalpy of formation of oxygen (O2) is 0 kJ/mol.
A. -110.5 kJ/mol
B. -120.5 kJ/mol
C. -130.5 kJ/mol
D. -140.5 kJ/mol
Question 13
Determine the number of moles of oxygen gas produced when 2.5 moles of calcium carbonate are decomposed according to the equation: CaCO3(s) → CaO(s) + CO2(g) + 1/2O2(g).
A. 1.25
B. 2.5
C. 3.75
D. 5
Question 14
A sample of a gas at 25°C and 1 atm has a volume of 2.5 L. If the pressure is increased to 2 atm, what is the new volume of the gas?
A. 1.25 L
B. 1.5 L
C. 2.0 L
D. 2.5 L
Question 15
In the electrolysis of a solution of silver nitrate, the anode is made of platinum and the cathode is made of silver. The reaction at the anode is:
A. 2Ag+(aq) + 2e- → Ag(s)
B. 2Ag+(aq) + 2e- → Ag2O(s)
C. 2Ag+(aq) + 2e- → Ag2O2(s)
D. 2Ag+(aq) + 2e- → Ag2O3(s)

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: