POST UTME ACHIEVERS UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1000.0-mL sample of a 0.100 M NaOH solution is mixed with a 1000.0-mL sample of a 0.100 M HCl solution. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 2
Determine the molar mass of a compound that contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass.
A. 12.0 g/mol
B. 24.0 g/mol
C. 36.0 g/mol
D. 48.0 g/mol
Question 3
A sample of a gas at 300 K and 1 atm is compressed to 2 atm at cons\tant temperature. What is the new volume of the gas?
A. 0.5 V1
B. V1
C. 2V1
D. 3V1
Question 4
A 200.0-mL sample of a 0.100 M NaOH solution is mixed with a 200.0-mL sample of a 0.100 M HCl solution. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 5
Determine the molar mass of a polymer with the following molecular formula: C10H8O4. Given that the atomic masses of carbon, hydrogen, and oxygen are 12.01 g/mol, 1.01 g/mol, and 16.00 g/mol, respectively.
A. 120.12 g/mol
B. 128.12 g/mol
C. 136.12 g/mol
D. 144.12 g/mol
Question 6
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 7
A 0.250 M solution of HCl is titrated with 0.250 M NaOH. Calculate the pH of the solution after 25.0 mL of NaOH has been added.
A. 1.00
B. 1.25
C. 1.50
D. 1.75
Question 8
The half-life of a radioactive subs\tance is 3.00 days. If 150.0 mg of the subs\tance is present initially, how much will remain after 15.0 days?
A. 37.5 mg
B. 75.0 mg
C. 112.5 mg
D. 150.0 mg
Question 9
A 0.5 M solution of sodium hydroxide (NaOH) is prepared by dissolving 10.0 g of NaOH in 1.0 L of water. What is the concentration of the solution in terms of molarity?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 10
A 0.1 M solution of a weak acid, HA, is titrated with 0.1 M NaOH. The pH of the solution at the equivalence point is 7. Calculate the pKa of the acid.
A. 1
B. 2
C. 3
D. 4
Question 11
A 2.50-g sample of a metal oxide is heated in a crucible until it decomposes completely. If 1.25 g of oxygen is collected, what is the empirical formula of the metal oxide?
A. FeO
B. Fe2O3
C. Fe3O4
D. FeO2
Question 12
The reaction between nitrogen dioxide and water is an example of a redox reaction. What is the oxidation state of nitrogen in NO2?
A. +2
B. +4
C. +6
D. +8
Question 13
A 25.0-mL sample of a 0.100 M NaOH solution is mixed with a 25.0-mL sample of a 0.100 M HCl solution. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 14
Determine the number of moles of oxygen gas (O2) required to react with 2.5 moles of propane (C3H8) according to the balanced equation: 2C3H8 + 19O2 → 12CO2 + 14H2O.
A. 1.5 moles
B. 2.5 moles
C. 3.75 moles
D. 4.5 moles
Question 15
A 2.0 g sample of a metal M is heated in a crucible until it is completely oxidized. The mass of the crucible and the oxide formed is 3.2 g. What is the molar mass of M?
A. 40 g/mol
B. 55 g/mol
C. 70 g/mol
D. 80 g/mol

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