POST UTME UNN 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The diagram below shows the energy levels of an atom. Which of the following transitions represents the absorption of energy?
A. A → B
B. B → A
C. A → C
D. C → A
Question 2
A gas at a pressure of 2 atm and a temperature of 300 K is allowed to expand to twice its original volume. What is the final pressure of the gas?
A. 1 atm
B. 2 atm
C. 4 atm
D. 6 atm
Question 3
A sample of iron (Fe) is electrolytically deposited from a solution of Fe2+ ions. If the electrolysis is carried out at a current of 2.5 A for 2 hours, what mass of iron is deposited?
A. 0.25 kg
B. 0.5 kg
C. 0.75 kg
D. 1.0 kg
Question 4
A 1.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 1 L of water. Calculate the pOH of the solution.
A. 0.5
B. 1.0
C. 1.5
D. 2.0
Question 5
A solution of 0.1 M HCl is mixed with a solution of 0.2 M NaOH. Calculate the pH of the resulting solution.
A. 1
B. 2
C. 3
D. 4
Question 6
The element with atomic number 12 is _______.
A. Mg
B. Ca
C. K
D. Na
Question 7
Determine the type of hybridization of the central atom in the molecule SO2.
A. sp3
B. sp2
C. sp
D. dsp3
Question 8
The half-life of a radioactive subs\tance is 5 days. If 100 mg of the subs\tance is present initially, how much will remain after 15 days?
A. 12.5 mg
B. 25.0 mg
C. 50.0 mg
D. 100 mg
Question 9
A sample of $\text{CaCO}_3$ weighing 25.0 g is heated to produce $\text{CaO}$ and $\text{CO}_2$. If the mass of $\text{CaO}$ produced is 15.0 g, what is the mass of $\text{CO}_2$ produced?
A. 5.0 g
B. 10.0 g
C. 15.0 g
D. 20.0 g
Question 10
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 11
Determine the number of moles of glu\cose (C6H12O6) that can be produced from 2.5 mol of ethene (C2H4) in the following reaction: C2H4 + 3O2 → C2H4O2 + 2CO2. Assume that the reaction proceeds to completion.
A. 1.5 mol
B. 2.0 mol
C. 2.5 mol
D. 3.0 mol
Question 12
A sample of air contains 20% O2, 70% N2, and 10% CO2 by volume. Calculate the partial pressure of CO2 in the sample at 1 atm.
A. 0.1 atm
B. 0.2 atm
C. 0.3 atm
D. 0.4 atm
Question 13
Determine the number of unpaired electrons in the ground state of a copper atom, given that the atomic number of copper is 29 and the electron configuration is [Ar] 3d10 4s1.
A. 1
B. 2
C. 3
D. 4
Question 14
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the monomer.
A. 200 g/mol
B. 250 g/mol
C. 300 g/mol
D. 350 g/mol
Question 15
A metal has a density of 8.5 g/cm3 and a molar mass of 65 g/mol. Calculate the number of moles of the metal in a 2.5 g sample.
A. 0.038 mol
B. 0.048 mol
C. 0.058 mol
D. 0.068 mol

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