POST UTME NILE UNIVERSITY 2020 Chemistry | Objective

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Question 1
A 10 mL sample of a solution containing 0.1 M HCl is titrated with 0.1 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 10 mL
B. 20 mL
C. 30 mL
D. 40 mL
Question 2
A diagram of a chemical apparatus is shown below. If the apparatus is used to measure the pH of a solution, what is the pH of the solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 3
Which of the following compounds is a nonpolar molecule?
A. CH4
B. CO2
C. H2O
D. NH3
Question 4
A reaction is carried out in a bomb calorimeter at cons\tant volume. The reaction is exothermic and releases 12.5 kJ of heat energy. If the initial temperature of the reaction mixture is 298 K, what is the change in internal energy (ΔU) for the reaction?
A. 12.5 kJ
B. -12.5 kJ
C. 0 kJ
D. 25 kJ
Question 5
A 2.00 L flask contains 0.500 M H2(g) at 25°C. If 0.250 mol of H2(g) is added to the flask, what is the new pressure of H2(g)?
A. 0.500 atm
B. 0.750 atm
C. 1.00 atm
D. 1.25 atm
Question 6
A catalyst is added to a reaction mixture containing 1.0 M H2 and 1.0 M O2. The reaction is as follows: 2H2 + O2 → 2H2O. If the reaction is allowed to proceed for 10 minutes, what is the concentration of H2 remaining?
A. 0.5 M
B. 0.6 M
C. 0.7 M
D. 0.8 M
Question 7
A 10.0 g sample of a metal is heated to 100°C and then dropped into 50.0 mL of water at 20.0°C. If the final temperature of the water is 22.5°C, what is the specific heat capacity of the metal?
A. 0.500 J/g°C
B. 1.00 J/g°C
C. 2.00 J/g°C
D. 4.00 J/g°C
Question 8
The s\tandard electrode potential for the reaction Zn2+ + 2e- → Zn is -0.76 V. Calculate the s\tandard electrode potential for the reaction Zn → Zn2+ + 2e-.
A. -0.76 V
B. 0.76 V
C. 1.52 V
D. -1.52 V
Question 9
A metal M reacts with chlorine gas to form a white solid product. The reaction is as follows: 2M(s) + Cl2(g) → 2MCl(s). If 2.5 g of MCl is produced, calculate the number of moles of MCl produced.
A. 0.05 mol
B. 0.06 mol
C. 0.07 mol
D. 0.08 mol
Question 10
A 0.1 M solution of a weak acid HA is mixed with 0.1 M NaOH. If the resulting solution has a pH of 4.5, what is the value of the dissociation cons\tant of the acid (Ka)?
A. 1.0 x 10^-5
B. 1.0 x 10^-4
C. 1.0 x 10^-3
D. 1.0 x 10^-2
Question 11
A 0.1 M solution of a weak acid HA is mixed with 0.1 M NaOH. If the resulting solution has a pH of 4.5, what is the value of the dissociation cons\tant of the acid (Ka)?
A. 1.0 x 10^-5
B. 1.0 x 10^-4
C. 1.0 x 10^-3
D. 1.0 x 10^-2
Question 12
A 1.0 M solution of a weak base is titrated with 1.0 M HCl. At the equivalence point, the pH of the solution is 7. Calculate the initial concentration of the base.
A. 1 x 10^-1 M
B. 1 x 10^-2 M
C. 1 x 10^-3 M
D. 1 x 10^-4 M
Question 13
A redox reaction occurs between Fe2+ and Cr2+ ions. The reaction is as follows: Fe2+ + Cr2+ → Fe3+ + Cr3+. If 2.5 g of Fe2+ ions are added to 1.0 L of a solution containing 0.1 M Cr2+ ions, what is the concentration of Fe3+ ions produced?
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 14
A 2.0 g sample of a compound is found to have a mass of 2.5 g when placed in a 10.0 mL solution of 0.1 M NaOH. What is the molar mass of the compound?
A. 50.0 g/mol
B. 100.0 g/mol
C. 150.0 g/mol
D. 200.0 g/mol
Question 15
A diagram of a titration setup is shown below. If 25.0 mL of 0.1 M NaOH is required to reach the equivalence point, what is the concentration of the acid (HA)?
A. 0.01 M
B. 0.1 M
C. 1.0 M
D. 10.0 M

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