POST UTME UNIOSUN 2024 Chemistry | Objective

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Question 1
A 0.1 M solution of sodium sulfate (Na2SO4) is prepared by dissolving 2.5 g of the salt in 100 mL of water. Calculate the molarity of the solution.
A. 0.025 M
B. 0.05 M
C. 0.1 M
D. 0.2 M
Question 2
A 5.0 g sample of a metal hydroxide is dissolved in 50 mL of water to produce a solution containing 0.1 M OH- ions. Calculate the molar concentration of the metal ions in the solution.
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 3
A 2.0 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 1.5 g. Calculate the percentage yield of the metal oxide.
A. 75%
B. 80%
C. 85%
D. 90%
Question 4
A 2.50 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 1.20 L at 25°C and 1 atm. The volume of H2O produced is 0.50 L at 25°C and 1 atm. Calculate the empirical formula of the compound.
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 5
A 2.50 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 1.20 L at 25°C and 1 atm. The volume of H2O produced is 0.50 L at 25°C and 1 atm. Calculate the empirical formula of the compound.
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 6
A solution contains 5.00 g of NaCl in 100.0 mL of water. Calculate the molarity of the solution.
A. 0.50 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 7
A solution of a non-metallic oxide is prepared by dissolving the oxide in water. Which of the following is a correct interpretation of the data?
A. The solution is acidic.
B. The solution is basic.
C. The solution is neutral.
D. The solution is a salt.
Question 8
A 2.0 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 1.5 g. Calculate the percentage yield of the metal oxide.
A. 75%
B. 80%
C. 85%
D. 90%
Question 9
A solution contains 5.00 g of NaCl in 100.0 mL of water. Calculate the molarity of the solution.
A. 0.50 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 10
A 2.50 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 1.20 L at 25°C and 1 atm. The volume of H2O produced is 0.50 L at 25°C and 1 atm. Calculate the empirical formula of the compound.
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 11
The element with atomic number 12 is classified as a metal in the periodic table. Which of the following is a characteristic of this element?
A. It is a good conductor of electricity.
B. It is a poor conductor of electricity.
C. It is a noble gas.
D. It is a ha\logen.
Question 12
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of methane (CH4(g)) u\sing the following equation: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l).
A. -890.3 kJ/mol
B. -890.4 kJ/mol
C. -890.5 kJ/mol
D. -890.6 kJ/mol
Question 13
A mixture of 0.5 mol of NaCl and 0.2 mol of KNO3 is dissolved in 1 L of water. Calculate the molar concentration of Cl- ions in the solution.
A. 0.5 M
B. 0.6 M
C. 0.7 M
D. 0.8 M
Question 14
A solution contains 5.00 g of NaCl in 100.0 mL of water. Calculate the molarity of the solution.
A. 0.50 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 15
The reaction of chlorine gas with sodium hydroxide solution is a classic example of a redox reaction. Write the balanced chemical equation for this reaction and identify the oxidation and reduction half-reactions.
A. 2NaOH + Cl2 → NaCl + NaClO + H2O
B. 2NaOH + Cl2 → NaClO + NaCl + H2O
C. 2NaOH + Cl2 → NaCl + NaClO3 + H2O
D. 2NaOH + Cl2 → NaClO + NaClO3 + H2O

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