POST UTME ACHIEVERS UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 10.0 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 22.5 mL at 25°C and 1 atm. What is the empirical formula of the compound?
A. CH4
B. C2H4
C. C3H6
D. C4H8
Question 2
The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). If 2.5 g of zinc metal is added to 100 mL of 0.1 M copper(II) sulfate solution, calculate the number of moles of copper metal deposited at the cathode.
A. 0.025 mol
B. 0.05 mol
C. 0.075 mol
D. 0.1 mol
Question 3
A 2.5 M solution of HCl is titrated with 0.5 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, calculate the number of moles of HCl present in the solution.
A. 0.0125 mol
B. 0.01275 mol
C. 0.01325 mol
D. 0.01375 mol
Question 4
The diagram below shows a titration setup. Identify the part labeled A.
A. Burette
B. Beaker
C. Test tube
D. Cylinder
Question 5
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of H2(g)?
A. 0 kJ/mol
B. 10 kJ/mol
C. 20 kJ/mol
D. 30 kJ/mol
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of H2O(l) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol.
A. -285.8 kJ/mol
B. -286.8 kJ/mol
C. -287.8 kJ/mol
D. -288.8 kJ/mol
Question 7
A solution containing 0.1 M HCl is titrated with 0.1 M NaOH. If 20 mL of NaOH is added, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 8
A 2.5 M solution of HCl is mixed with a 1.8 M solution of NaOH. What is the resulting pH?
A. 1
B. 2
C. 3
D. 4
Question 9
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.0500 M
B. 0.100 M
C. 0.200 M
D. 0.500 M
Question 10
A 1.0 L flask contains 0.2 mol of CO2 at 25°C. Calculate the partial pressure of CO2 in the flask.
A. 0.5 atm
B. 0.7 atm
C. 0.9 atm
D. 1.1 atm
Question 11
A 0.5 M solution of K2Cr2O7 is electrolyzed u\sing a platinum electrode. What is the mass of Cr2O3 produced after 2 hours of electrolysis?
A. 10 g
B. 20 g
C. 30 g
D. 40 g
Question 12
The reaction between sodium hydroxide and acetic acid is represented by the equation: CH3COOH + NaOH → CH3COONa + H2O. If 1.2 g of CH3COOH is reacted with an excess of NaOH, what is the limiting reac\tant?
A. CH3COOH
B. NaOH
C. CH3COONa
D. H2O
Question 13
Determine the number of moles of oxygen gas (O2) produced at STP when 2.50 g of potassium chlorate (KClO3) decomposes according to the equation: 2KClO3(s) → 2KCl(s) + 3O2(g).
A. 0.125 mol
B. 0.250 mol
C. 0.500 mol
D. 1.00 mol
Question 14
A solution of 0.1 M sodium hydroxide is prepared by dissolving 3.5 g of sodium hydroxide in 100 mL of water. What is the concentration of the solution in terms of molarity?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 15
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, what mass of the subs\tance will remain after 15 years?
A. 12.5 g
B. 25 g
C. 50 g
D. 100 g

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: