POST UTME NILE UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A reaction has a rate cons\tant of 2.5 s^-1. If the initial concentration of the reac\tant is 0.1 M, calculate the concentration of the reac\tant after 10 minutes.
A. 0.05 M
B. 0.075 M
C. 0.1 M
D. 0.125 M
Question 2
A 1.0 M solution of a weak acid is titrated with 1.0 M NaOH. At the equivalence point, the pH of the solution is 7. Calculate the initial concentration of the acid.
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 3
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, ΔHf(C(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 4
A solution contains 10 g of sodium chloride (NaCl) per 100 g of water. What is the molarity of the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 5
A colloidal solution contains 10 g of starch in 100 g of water. What is the volume of the solution that will have a concentration of 0.1 g/mL?
A. 100 mL
B. 200 mL
C. 500 mL
D. 1000 mL
Question 6
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 7
A 2.50 g sample of a metal is heated to 100°C and then dropped into 25.0 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
A sample of a gas has a volume of 2 L at a pressure of 1 atm and a temperature of 300 K. What is the volume of the gas at a pressure of 2 atm and a temperature of 400 K?
A. 4 L
B. 6 L
C. 8 L
D. 10 L
Question 9
A solution contains 0.100 M NaCl(aq). What is the concentration of Cl- ions in the solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 10
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, calculate the volume of HCl required to reach the equivalence point.
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 11
A solution contains 0.5 M H2SO4 and 0.5 M NaOH. What is the concentration of H+ ions in the solution?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1 M
Question 12
A 0.1 M solution of a monoprotic acid is titrated with 0.1 M NaOH. At the equivalence point, the pH of the solution is 7. Calculate the initial concentration of the acid.
A. 1 x 10^-3 M
B. 1 x 10^-4 M
C. 1 x 10^-5 M
D. 1 x 10^-6 M
Question 13
A sample of a metal oxide is heated in a crucible. The resulting gas is collected over water and found to have a volume of 2.5 L at 20°C and 1.5 atm. If the gas is CO2, calculate the number of moles of CO2 produced.
A. 0.1 mol
B. 0.2 mol
C. 0.3 mol
D. 0.4 mol
Question 14
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 15
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

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