POST UTME OAU 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 25.0 mL sample of 0.100 M HCl(aq) is titrated with 0.100 M NaOH(aq). What is the volume of NaOH(aq) required to reach the equivalence point?
A. 25.0 mL
B. 50.0 mL
C. 75.0 mL
D. 100 mL
Question 2
A 25.0 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 15.0 g. Calculate the molar mass of the metal carbonate.
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 3
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, what is the value of the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^-1?
A. 1.0 x 10^6 s^-1
B. 1.0 x 10^7 s^-1
C. 1.0 x 10^8 s^-1
D. 1.0 x 10^9 s^-1
Question 4
A 1.00 g sample of a metal is heated in a crucible to produce a 0.500 g sample of the metal oxide. What is the percentage yield of the metal oxide?
A. 50.0%
B. 75.0%
C. 80.0%
D. 90.0%
Question 5
A 1.00 g sample of a metal is heated in a crucible to produce a 0.500 g sample of the metal oxide. What is the molar mass of the metal?
A. 50.0 g/mol
B. 75.0 g/mol
C. 100 g/mol
D. 125 g/mol
Question 6
The s\tandard enthalpy of formation of carbon monoxide (CO) is -110.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mole of carbon (C) according to the equation: C + 1/2O2 → CO.
A. -110.5 kJ
B. -111.5 kJ
C. -112.5 kJ
D. -113.5 kJ
Question 7
A 1.00 M solution of HCl is titrated with 1.00 M NaOH. What is the pH of the solution after 50.0 mL of NaOH has been added?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 8
A 100.0 mL sample of a 0.1 M solution of H2SO4 is mixed with 100.0 mL of a 0.1 M solution of NaOH. What is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 9
A 2.5 L sample of an ideal gas at 27°C and 1 atm is compressed to 1.5 L at 37°C. Calculate the work done on the gas in kJ.
A. 3.5 kJ
B. -3.5 kJ
C. 4.2 kJ
D. -4.2 kJ
Question 10
Determine the pH of a 0.1 M solution of HCl after 10 mL of 0.1 M NaOH has been added to 20 mL of the HCl solution. The initial pH of the HCl solution is 1.0.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 11
A solution contains 0.1 M Fe^3+ ions. If 10 mL of 1 M NaOH is added to 90 mL of the solution, what is the concentration of Fe(OH)3 that forms?
A. 0.01 M
B. 0.1 M
C. 0.5 M
D. 1 M
Question 12
A sample of nitrogen gas occupies a volume of 2.50 L at a pressure of 1.00 atm and a temperature of 298 K. What is the number of moles of nitrogen gas present?
A. 0.0100 mol
B. 0.0200 mol
C. 0.0300 mol
D. 0.0400 mol
Question 13
The s\tandard enthalpy of formation of carbon dioxide (CO2) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mole of carbon (C) according to the equation: C + O2 → CO2.
A. -393.5 kJ
B. -394.5 kJ
C. -395.5 kJ
D. -396.5 kJ
Question 14
A 50.0 mL sample of a 0.1 M solution of FeCl3 is mixed with 50.0 mL of a 0.1 M solution of NaOH. What is the concentration of the resulting solution?
A. 0.05 M
B. 0.10 M
C. 0.15 M
D. 0.20 M
Question 15
A 2.0 L sample of a gas at 25°C and 1.0 atm is collected over water at 25°C. The vapor pressure of water at 25°C is 23.8 mmHg. Calculate the partial pressure of the gas.
A. 0.97 atm
B. 0.98 atm
C. 0.99 atm
D. 1.0 atm

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