POST UTME EKSU 2020 Chemistry | Objective

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Question 1
A 2.00 L flask contains 0.500 M H2(g) at 25.0°C. What is the partial pressure of H2(g) in the flask?
A. 0.500 atm
B. 1.00 atm
C. 1.50 atm
D. 2.00 atm
Question 2
A sample of a gas occupies 1.50 L at 20.0°C and 0.500 atm. What is the volume of the gas at 30.0°C and 1.00 atm?
A. 1.75 L
B. 2.00 L
C. 2.25 L
D. 2.50 L
Question 3
The s\tandard enthalpy of formation (ΔHf°) for H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy change (ΔH°) for the reaction: H2(g) + 1/2O2(g) → H2O(l).
A. -285.8 kJ/mol
B. -286.2 kJ/mol
C. -286.5 kJ/mol
D. -286.0 kJ/mol
Question 4
A polymer sample is analyzed u\sing gel permeation chromatography (GPC). The chromatogram shows a peak at 10 minutes with a retention volume of 20 mL. Calculate the molecular weight of the polymer, assuming a calibration curve with a slope of 1.00 mL/min.
A. 10^4 g/mol
B. 10^5 g/mol
C. 10^6 g/mol
D. 10^7 g/mol
Question 5
A solution of 0.1 M NaCl is electrolyzed u\sing a platinum electrode. Calculate the mass of chlorine gas (Cl2) produced at the anode after 2 hours, assuming a current of 1 A and a cell potential of 2.0 V.
A. 0.50 g
B. 1.00 g
C. 1.50 g
D. 2.00 g
Question 6
A 25 mL sample of 0.5 M H2SO4 is titrated with 0.5 M NaOH. Calculate the number of moles of H2SO4.
A. 0.1
B. 0.2
C. 0.3
D. 0.4
Question 7
A 1.0 M solution of ΔFeClγ is electrolyzed u\sing a platinum electrode. Calculate the mass of ΔFe deposited after 1 hour, given that the current density is 10 A/m² and the electrode area is 0.05 m².
A. 0.25 g
B. 0.50 g
C. 0.75 g
D. 1.0 g
Question 8
The s\tandard enthalpy of formation of ΔFe(OH)γ is -826.4 kJ/mol. Calculate the s\tandard Gibbs free energy of formation of ΔFe(OH)γ at 298 K.
A. -826.4 kJ/mol
B. -826.4 kJ/mol + 298 J/mol
C. -826.4 kJ/mol - 298 J/mol
D. -826.4 kJ/mol + 298 kJ/mol
Question 9
A 25.0 mL sample of 0.100 M HCl is added to 50.0 mL of 0.0500 M NaOH. Calculate the number of moles of HCl that react with NaOH.
A. 0.00250 mol
B. 0.00300 mol
C. 0.00200 mol
D. 0.00150 mol
Question 10
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution after adding 10 mL of 0.1 M HCl?
A. 1
B. 2
C. 3
D. 4
Question 11
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CH4(g) if the s\tandard enthalpy of formation of C(s) is -394.4 kJ/mol and the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol.
A. -74.8
B. -74.9
C. -75.0
D. -75.1
Question 12
A 10% solution of sulfuric acid (H2SO4) is mixed with a 20% solution of sodium hydroxide (NaOH). If 50 mL of the sulfuric acid solution is mixed with 100 mL of the sodium hydroxide solution, what is the concentration of the resulting solution?
A. 15% H2SO4
B. 12% H2SO4
C. 18% H2SO4
D. 20% H2SO4
Question 13
A sample of nitrogen gas (N2) occupies a volume of 2.5 L at a pressure of 1 atm and a temperature of 298 K. Calculate the number of moles of N2 present.
A. 0.1 mol
B. 0.2 mol
C. 0.3 mol
D. 0.4 mol
Question 14
A diagram of a redox reaction is shown below. If 10 mL of 0.1 M FeCl3 is added to 10 mL of 0.1 M NaOH, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 15
A sample of nitrogen gas (N2) at 25°C and 1 atm is heated to 50°C. Calculate the new volume of the gas, assuming the temperature change is isothermal.
A. 2.00 L
B. 2.50 L
C. 3.00 L
D. 3.50 L

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