POST UTME UNIPORT 2024 Chemistry | Objective

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Question 1
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of formation of H2(g) + 1/2 O2(g) → H2O(l).
A. -285.8 kJ/mol
B. 0 kJ/mol
C. 285.8 kJ/mol
D. 0 kJ/mol
Question 2
A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: 2X + Cl2 → 2XCl. If 2.5 g of X is reacted with 1.5 g of Cl2, what is the limiting reac\tant?
A. X
B. Cl2
C. Both X and Cl2 are limiting reac\tants
D. Neither X nor Cl2 is a limiting reac\tant
Question 3
A 0.5 L flask contains 0.2 mol of an ideal gas at 37°C. Calculate the number of moles of gas that will be present in a 1.0 L flask at 27°C.
A. 0.1 mol
B. 0.2 mol
C. 0.3 mol
D. 0.4 mol
Question 4
A sample of a non-metallic element, sulfur, is heated in a crucible. The resulting gas is collected over water and found to have a volume of 2.50 L at 25°C and 1.00 atm. What is the molar mass of sulfur?
A. 32.1 g/mol
B. 40.1 g/mol
C. 48.1 g/mol
D. 56.1 g/mol
Question 5
A 0.1 M solution of FeCl3 is mixed with a 0.1 M solution of NaOH. The resulting precipitate is filtered and dried. What is the molar mass of the precipitate?
A. 159 g/mol
B. 159.7 g/mol
C. 160 g/mol
D. 160.5 g/mol
Question 6
The s\tandard electrode potential of the reaction Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s) is 1.56 V. Calculate the s\tandard electrode potential of the reaction Zn(s) + 2Cu2+(aq) → Zn2+(aq) + 2Cu+(aq).
A. 0.34 V
B. 1.56 V
C. 2.10 V
D. 0.34 V
Question 7
Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K, given that the initial concentration of NO is 0.1 M and the half-life of the reaction is 10 s.
A. 1.0 × 10^\( -2 \) s^\( -1 \)
B. 2.0 × 10^\( -2 \) s^\( -1 \)
C. 3.0 × 10^\( -2 \) s^\( -1 \)
D. 4.0 × 10^\( -2 \) s^\( -1 \)
Question 8
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. Calculate the pH of the solution after 50 mL of NaOH has been added. The dissociation cons\tant for HCl is 1.0 × 10^-7.
A. 1.0
B. 1.5
C. 2.0
D. 2.5
Question 9
A solution of 0.5 M HCl is titrated with a solution of 0.5 M NaOH. What is the concentration of the acid after the addition of 25 mL of NaOH?
A. 0.25 M
B. 0.5 M
C. 1 M
D. 2 M
Question 10
A 0.1 M solution of CuSO4 is mixed with a 0.1 M solution of NaOH. The resulting precipitate is filtered and dried. What is the molar mass of the precipitate?
A. 159 g/mol
B. 159.7 g/mol
C. 160 g/mol
D. 160.5 g/mol
Question 11
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the solution
B. To measure the pH of the solution
C. To measure the temperature of the solution
D. To measure the density of the solution
Question 12
A solution of sodium hydroxide (NaOH) is prepared by dissolving 10 g of NaOH in 100 cm³ of water. What is the concentration of the solution in moles per liter?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 13
The s\tandard electrode potential of the reaction Cu2+(aq) + 2e- → Cu(s) is 0.34 V. Calculate the s\tandard electrode potential of the reaction Cu(s) → Cu2+(aq) + 2e-.
A. -0.34 V
B. 0.34 V
C. 1.56 V
D. -0.34 V
Question 14
Determine the number of moles of carbon dioxide produced when 2.5 g of calcium carbonate is heated in a crucible.
A. 0.05 mol
B. 0.10 mol
C. 0.15 mol
D. 0.20 mol
Question 15
A solution of hydrochloric acid (HCl) is titrated with a solution of sodium hydroxide (NaOH). The initial pH of the acid solution is 2.50. After the addition of 25.0 mL of NaOH solution, the pH of the solution is 7.00. What is the concentration of the HCl solution?
A. 0.100 M
B. 0.500 M
C. 1.00 M
D. 2.00 M

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