POST UTME UNILORIN 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The rate cons\tant of a first-order reaction is 0.05 min^-1. If the initial concentration of the reac\tant is 0.1 M, what is the concentration after 10 minutes?
A. 0.01 M
B. 0.02 M
C. 0.03 M
D. 0.04 M
Question 2
A solution of sodium hydroxide is titrated with a solution of hydrochloric acid. The reaction is as follows: NaOH + HCl → NaCl + H_{2}O. What is the pH of the solution after the reaction is complete?
A. 7
B. 9
C. 11
D. 13
Question 3
The reaction between sulfuric acid and sodium hydroxide is a neutralization reaction. If 25.0 mL of 1.0 M H2SO4 is mixed with 25.0 mL of 1.0 M NaOH, what is the concentration of the resulting solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M
Question 4
A 1.00 L flask contains 0.500 mol of $\text{O}_2$ at 25.0°C. What is the partial pressure of $\text{O}_2$ in the flask?
A. 0.500 atm
B. 1.00 atm
C. 2.00 atm
D. 3.00 atm
Question 5
The atomic radius of an element in the periodic table decreases as you move from left to right across a period. Which of the following elements has an atomic radius that is closest to that of carbon?
A. Boron (B)
B. Nitrogen (N)
C. Oxygen (O)
D. Fluorine (F)
Question 6
A 1.00 L solution of $\text{H}_2$O contains 0.500 g of $\text{CaCl}_2$. What is the concentration of $\text{Cl}^-$ ions in the solution?
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 7
A 2.00 M solution of $\text{H}_2$SO$_4$ is titrated with 0.500 M $\text{NaOH}$. What is the pH of the solution after 25.0 mL of $\text{NaOH}$ has been added?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 8
A 1.50-g sample of a polymer is dissolved in 50.0 mL of a solvent. If the polymer has a molar mass of 2.00 x 10^5 g/mol and the density of the solution is 1.20 g/mL, calculate the number of moles of polymer present in the solution.
A. 0.00750 mol
B. 0.00755 mol
C. 0.00760 mol
D. 0.00765 mol
Question 9
A metal M reacts with oxygen gas to form a white solid. The reaction is as follows: 4M + 3O_{2} → 2M_{2}O_{3}. Identify the metal M.
A. Al
B. Fe
C. Cu
D. Zn
Question 10
A redox reaction involves the oxidation of \( Fe^{2+} \) to \( Fe^{3+} \) and the reduction of \( MnO_4^- \) to \( Mn^{2+} \). What is the oxidation number of manganese in \( MnO_4^- \)?
A. +2
B. +4
C. +6
D. +8
Question 11
A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is required to neutralize 20 mL of a weak acid, calculate the concentration of the acid
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 12
The half-reaction for the reduction of oxygen gas is: O_{2} + 4H^{+} + 4e^{-} → 2H_{2}O. What is the oxidation number of oxygen in the product?
A. -2
B. +2
C. +1
D. -1
Question 13
A 2.00 M solution of HCl is titrated with a 1.00 M solution of NaOH. If 30.0 mL of NaOH is required to reach the equivalence point, calculate the number of moles of HCl present in the original solution.
A. 0.0600 mol
B. 0.0605 mol
C. 0.0610 mol
D. 0.0615 mol
Question 14
A solution of 0.5 M NaCl is prepared by dissolving 25.0 g of NaCl in 1.0 L of water. What is the concentration of Na+ ions in the solution?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1.0 M
Question 15
A sample of oxygen gas occupies a volume of 1.0 L at a pressure of 2.0 atm. What is the volume of the gas if the pressure is increased to 4.0 atm?
A. 0.5 L
B. 1.0 L
C. 1.5 L
D. 2.0 L

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