POST UTME BELLS UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 0.5 M solution of HCl is titrated with 0.5 M NaOH. What is the pH of the solution after the reaction is complete?
A. 1
B. 2
C. 3
D. 4
Question 2
The s\tandard enthalpy change of formation of carbon dioxide (CO2) is -393.5 kJ/mol. If 2.50 mol of CO2 is produced at 25°C, what is the total enthalpy change for the reaction?
A. -987.5 kJ
B. -1,225 kJ
C. -1,563 kJ
D. -1,875 kJ
Question 3
A 2.0 L flask contains 0.50 mol of an ideal gas at 298 K. Calculate the root mean square speed of the gas molecules.
A. 1.4 x 10^2 m/s
B. 1.4 x 10^3 m/s
C. 1.4 x 10^4 m/s
D. 1.4 x 10^5 m/s
Question 4
A 2.0 M solution of H2SO4 is titrated with 1.0 M NaOH. What is the pH of the solution after the reaction is complete?
A. 1
B. 2
C. 3
D. 4
Question 5
The atomic radius of a certain element is 100 pm. If the element has an electron configuration of [Ar] 4s2 3d5, what is the expected oxidation state of the element?
A. +2
B. +3
C. +5
D. +7
Question 6
A diagram of a simple plant cell is shown below. Identify the part labeled A.
A. Chloroplast
B. Mitochondria
C. Nucleus
D. Vacuole
Question 7
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. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 8
Determine the pH of a 0.1 M solution of HCl at 25°C.
A. 1
B. 2
C. 3
D. 4
Question 9
A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is added to 25 mL of 0.1 M HCl, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 10
A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: 2X + Cl2 → 2XCl. If 2.5 g of X reacts with 1.5 g of Cl2, what is the percentage yield of XCl?
A. 80%
B. 90%
C. 95%
D. 98%
Question 11
The rate cons\tant for a first-order reaction is 0.05 min^-1. What is the half-life of the reaction?
A. 10 min
B. 20 min
C. 30 min
D. 40 min
Question 12
A diagram of a simple electric circuit is shown below. If the current through the circuit is 2 A and the resis\tance is 10 Ω, what is the voltage across the circuit?
A. 20 V
B. 30 V
C. 40 V
D. 50 V
Question 13
The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). If 2.50 g of zinc metal is added to 100 cm3 of 0.0500 M copper(II) sulfate solution, what is the maximum mass of copper metal that can be deposited?
A. 1.25 g
B. 2.50 g
C. 3.75 g
D. 5.00 g
Question 14
A 2.5 L flask contains 0.50 mol of an ideal gas at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.
A. 1.01 x 10^2 kPa
B. 1.01 x 10^3 kPa
C. 1.01 x 10^4 kPa
D. 1.01 x 10^5 kPa
Question 15
A 2.00 M solution of hydrochloric acid (HCl) is mixed with a 1.00 M solution of sodium hydroxide (NaOH). If 50.0 cm3 of the HCl solution is added to 50.0 cm3 of the NaOH solution, what is the concentration of the resulting solution?
A. 0.500 M
B. 1.00 M
C. 1.50 M
D. 2.00 M

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