POST UTME BABCOCK UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.00 g sample of a metal \( atomic mass = 40.0 g/mol \) is dissolved in 25.0 mL of 0.100 M HCl. If the reaction is complete, what is the concentration of the metal ion in the solution?
A. 0.0200 M
B. 0.0300 M
C. 0.0400 M
D. 0.0500 M
Question 2
The half-life of a radioactive isotope is 2.00 days. If 25.0 mg of the isotope is present initially, what is the mass remaining after 4.00 days?
A. 6.25 mg
B. 12.5 mg
C. 18.75 mg
D. 25.0 mg
Question 3
A 1.0 M solution of H2SO4 is mixed with a 2.0 M solution of NaOH. What is the concentration of the resulting solution?
A. 1.0 M
B. 1.5 M
C. 2.0 M
D. 3.0 M
Question 4
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. -1206.0 kJ/mol
B. -1206.5 kJ/mol
C. -1207.0 kJ/mol
D. -1207.5 kJ/mol
Question 5
A sample of nitrogen gas (N2) has a volume of 2.5 L at a pressure of 1.0 atm and a temperature of 300 K. What is the number of moles of N2 present in the sample?
A. 0.01 mol
B. 0.05 mol
C. 0.1 mol
D. 0.5 mol
Question 6
A solution contains 2.5 g of NaCl in 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.25 M
C. 0.5 M
D. 1 M
Question 7
A 2.50 g sample of a non-metallic element is found to have a mass of 2.00 g after being heated in a crucible. If the element is a member of group 16, what is its identity?
A. S
B. Se
C. Te
D. Po
Question 8
The pH of a solution is 4.5. What is the concentration of hydrogen ions in the solution?
A. 1.0 \times 10^{-5} M
B. 1.0 \times 10^{-4} M
C. 1.0 \times 10^{-3} M
D. 1.0 \times 10^{-2} M
Question 9
A diagram of a simple electrolysis setup is provided below. What is the purpose of the salt bridge in this setup?
A. ( To prevent the mixing of the two solutions )
B. ( To allow the flow of electrons from one solution to the other )
C. ( To maintain electrical neutrality in the setup )
D. ( To increase the conductivity of the solution )
Question 10
A sample of nitrogen gas (N2) has a volume of 2.5 L at a pressure of 1.0 atm and a temperature of 300 K. What is the number of moles of N2 present in the sample?
A. 0.01 mol
B. 0.05 mol
C. 0.1 mol
D. 0.5 mol
Question 11
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is present initially, how much will remain after 15 years?
A. 10 g
B. 20 g
C. 50 g
D. 100 g
Question 12
A metal oxide has the formula M2O3. If 2.5 g of the oxide is dissolved in 50 mL of 0.1 M HCl, what is the number of moles of the metal that reacted with the acid?
A. 0.05 mol
B. 0.025 mol
C. 0.1 mol
D. 0.05 mol
Question 13
A sample of water has a pH of 7.0. What is the concentration of hydrogen ions in the sample?
A. 1.0 \times 10^{-7} M
B. 1.0 \times 10^{-6} M
C. 1.0 \times 10^{-5} M
D. 1.0 \times 10^{-4} M
Question 14
A solution contains 0.10 M NaOH and 0.10 M HCl. What is the pH of the solution?
A. 7
B. 6
C. 5
D. 4
Question 15
The half-reaction for the reduction of MnO4- is: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O. What is the s\tandard reduction potential of MnO4-?
A. 1.23 V
B. 1.51 V
C. 1.68 V
D. 1.85 V

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: