POST UTME ABU 2021 Chemistry | Objective

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Question 1
Determine the number of moles of $\text{CO}_2$ produced when 2.50 g of $\text{CaCO}_3$ is decomposed at cons\tant pressure and temperature.
A. 0.0500 mol
Correct B. 0.100 mol
C. 0.150 mol
D. 0.200 mol

Correct Answer: B

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Question 2
A solution contains 0.500 M $\text{Fe}^{2+}$ ions. What is the concentration of $\text{Fe}^{3+}$ ions if 0.0100 M $\text{KMnO}_4$ is added to the solution?
A. 0.00500 M
Correct B. 0.0100 M
C. 0.0150 M
D. 0.0200 M

Correct Answer: B

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Question 3
A 0.1000 M solution of $\text{HCl}$ is mixed with a 0.1000 M solution of $\text{NaOH}$. What is the concentration of $\text{HCl}$ after the reaction is complete?
A. 0.0500 M
B. 0.0750 M
Correct C. 0.100 M
D. 0.125 M

Correct Answer: C

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Question 4
A diagram of a titration setup is shown below.
A. The burette contains $\text{NaOH}$.
Correct B. The beaker contains $\text{HCl}$.
C. The burette contains $\text{HCl}$.
D. The beaker contains $\text{NaOH}$.

Correct Answer: B

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Question 5
A diagram of a chromatography setup is shown below.
Correct A. The column contains $\text{silica gel}$.
B. The beaker contains $\text{water}$.
C. The column contains $\text{water}$.
D. The beaker contains $\text{silica gel}$.

Correct Answer: A

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Question 6
The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of copper in the product Cu(s)?
A. 0
B. +1
Correct C. +2
D. -1

Correct Answer: C

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Question 7
A solution of 0.100 M NaCl is mixed with a solution of 0.100 M AgNO3. What is the concentration of AgCl(s) that precipitates out of the solution?
Correct A. 0.050 M
B. 0.100 M
C. 0.0500 M
D. 0.05000 M

Correct Answer: A

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Question 8
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
Correct A. -110.5 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol

Correct Answer: A

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Question 9
A 2.50 L flask contains 0.500 M H2(g) at 25°C. What is the partial pressure of H2(g) in the flask?
A. 0.100 atm
B. 0.200 atm
Correct C. 0.250 atm
D. 0.500 atm

Correct Answer: C

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Question 10
A solution of 0.100 M NaOH is mixed with a solution of 0.100 M HCl. What is the pH of the resulting solution?
Correct A. 7.00
B. 7.00
C. 7.00
D. 7.00

Correct Answer: A

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Question 11
Determine the s\tandard enthalpy of formation of CaO from the following data: ΔHf(Ca) = -1.85 kJ/mol, ΔHf(O) = -0.40 kJ/mol. The reaction is Ca + 1/2O2 → CaO.
A. -1.25 kJ/mol
Correct B. -1.75 kJ/mol
C. -2.25 kJ/mol
D. -2.75 kJ/mol

Correct Answer: B

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Question 12
A 2.5 M solution of HCl is mixed with a 2.5 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 13
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.0500 M
Correct B. 0.100 M
C. 0.150 M
D. 0.200 M

Correct Answer: B

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Question 14
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO?
Correct A. -110.5 kJ/mol
B. -210.5 kJ/mol
C. -310.5 kJ/mol
D. -410.5 kJ/mol

Correct Answer: A

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Question 15
A 1.0 M solution of H2SO4 is mixed with a 1.0 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 16
The reaction between sulfuric acid and sodium hydroxide is a classic example of a neutralization reaction. Write the balanced chemical equation for this reaction, including the state of each subs\tance.
Correct A. H2SO4 (aq) + 2NaOH (aq) → Na2SO4 (aq) + 2H2O (l)
B. H2SO4 (l) + 2NaOH (aq) → Na2SO4 (s) + 2H2O (g)
C. H2SO4 (aq) + NaOH (s) → Na2SO4 (aq) + H2O (l)
D. H2SO4 (l) + NaOH (aq) → Na2SO4 (aq) + H2O (l)

Correct Answer: A

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Question 17
A 25.0 mL sample of a solution containing 0.100 M NaCl is titrated with 0.100 M AgNO3. Calculate the volume of AgNO3 required to reach the equivalence point.
A. 12.5 mL
B. 25.0 mL
Correct C. 37.5 mL
D. 50.0 mL

Correct Answer: C

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Question 18
A 2.50 g sample of a polymer is dissolved in 50.0 mL of a solvent. Calculate the molarity of the polymer solution.
A. 0.100 M
B. 0.200 M
Correct C. 0.500 M
D. 1.00 M

Correct Answer: C

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Question 19
A 100 mL sample of a solution containing 0.500 M HCl is titrated with 0.500 M NaOH. Calculate the pH of the solution at the equivalence point.
A. 7.00
Correct B. 8.00
C. 9.00
D. 10.0

Correct Answer: B

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Question 20
A 50.0 mL sample of a solution containing 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 25.0 mL
Correct B. 50.0 mL
C. 75.0 mL
D. 100 mL

Correct Answer: B

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Question 21
A 100 mL sample of a solution containing 0.500 M H2SO4 is titrated with 0.500 M NaOH. Calculate the pH of the solution at the equivalence point.
A. 7.00
Correct B. 8.00
C. 9.00
D. 10.0

Correct Answer: B

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Question 22
A 50.0 mL sample of a solution containing 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 25.0 mL
Correct B. 50.0 mL
C. 75.0 mL
D. 100 mL

Correct Answer: B

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Question 23
A 100 mL sample of a solution containing 0.500 M H2SO4 is titrated with 0.500 M NaOH. Calculate the pH of the solution at the equivalence point.
A. 7.00
Correct B. 8.00
C. 9.00
D. 10.0

Correct Answer: B

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Question 24
A 50.0 mL sample of a solution containing 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 25.0 mL
Correct B. 50.0 mL
C. 75.0 mL
D. 100 mL

Correct Answer: B

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Question 25
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If the initial pH of the acid solution is 3.5, what is the pH after the addition of 20 mL of NaOH?
A. 4.5
Correct B. 5.5
C. 6.5
D. 7.5

Correct Answer: B

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