POST UTME OAU 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Determine the number of moles of oxygen gas (O2) produced at STP when 2.5 moles of potassium chlorate (KClO3) decompose according to the equation: 2KClO3(s) → 2KCl(s) + 3O2(g).
A. 1.5
B. 2.5
C. 3.75
D. 4.5
Question 2
A 10 mL sample of 0.5 M H2SO4 is titrated with 1 M NaOH. Calculate the number of moles of NaOH required.
A. 0.05
B. 0.1
C. 0.15
D. 0.2
Question 3
A $0.1,M$ solution of $HCl$ is titrated with a $0.1,M$ solution of $NaOH$. If $25,cm^3$ of $NaOH$ is required to reach the equivalence point, calculate the volume of $HCl$ in $cm^3$.
A. 50 cm^3
B. 75 cm^3
C. 100 cm^3
D. 125 cm^3
Question 4
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 5
A solution contains 0.1 M HCl and 0.1 M NaOH. Calculate the pH of the solution.
A. 1
B. 2
C. 3
D. 4
Question 6
A solution contains 0.1 M HCl and 0.1 M NaOH. Calculate the pH of the solution.
A. 1
B. 2
C. 3
D. 4
Question 7
A 2.00 L flask contains 0.100 mol of CO2 at 25°C. What is the pressure of the gas?
A. 0.100 atm
B. 0.500 atm
C. 1.00 atm
D. 2.00 atm
Question 8
A 25 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. Calculate the pH of the solution after the addition of 20 mL of NaOH.
A. 1
B. 2
C. 3
D. 4
Question 9
A sample of nitrogen gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 298 K. What is the number of moles of nitrogen gas present?
A. 0.1 mol
B. 0.2 mol
C. 0.3 mol
D. 0.4 mol
Question 10
A solution of potassium dichromate (K2Cr2O7) is titrated with a solution of iron(II) sulfate (FeSO4). The reaction is as follows: K2Cr2O7 + 6FeSO4 + 7H2O → K2SO4 + 2Cr(OH)3 + 6Fe(OH)3. If 25.0 mL of 0.100 M K2Cr2O7 is titrated with 0.0500 M FeSO4, what is the number of moles of FeSO4 required to react with the K2Cr2O7?
A. 0.00125 mol
B. 0.00250 mol
C. 0.00500 mol
D. 0.0125 mol
Question 11
A metal $M$ has a s\tandard electrode potential of $-0.5,V$. If a $1,M$ solution of $M^{2+}$ is electrolyzed at $25^circ C$, calculate the cell potential.
A. -0.5 V
B. -1 V
C. -1.5 V
D. -2 V
Question 12
A sample of a gas at 25°C and 1 atm is collected over water at 25°C. The vapor pressure of water at 25°C is 23.8 mmHg. What is the partial pressure of the gas?
A. 1.00 atm
B. 1.23 atm
C. 1.38 atm
D. 1.78 atm
Question 13
A solution contains 0.1 M Cu^2+ ions and 0.1 M SO_4^2- ions. What is the concentration of CuSO_4 in the solution?
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1.0 M
Question 14
A solution contains 0.1 M Cu^2+ ions and 0.1 M SO_4^2- ions. What is the concentration of CuSO_4 in the solution?
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1.0 M
Question 15
A solution of sodium chloride is electrolyzed u\sing a current of 5.0 A for 2.5 hours. What is the mass of chlorine gas produced at the anode?
A. 0.5 g
B. 1.0 g
C. 1.5 g
D. 2.0 g

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