POST UTME ACHIEVERS UNIVERSITY 2021 Chemistry | Objective

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Question 1
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
Correct D. 4

Correct Answer: D

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Question 2
A 25.0 mL sample of 0.500 M NaOH is titrated with 0.100 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.0125
Correct B. 0.0250
C. 0.0375
D. 0.0500

Correct Answer: B

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Question 3
A diagram of a titration setup is shown below. If 25.0 mL of 0.500 M NaOH is titrated with 0.100 M HCl, what is the pH of the solution at the equivalence point?
A. 7
B. 8
C. 9
Correct D. 10

Correct Answer: D

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Question 4
A 10.0 g sample of a metal carbonate is heated to produce a 5.00 g sample of the metal oxide. What is the molar mass of the metal carbonate?
A. 100
B. 150
Correct C. 200
D. 250

Correct Answer: C

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Question 5
A diagram of a metal oxide is shown below. If the molar mass of the metal oxide is 200 g/mol, what is the molar mass of the metal?
A. 100
B. 150
Correct C. 200
D. 250

Correct Answer: C

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Question 6
Determine the molar mass of a polymer with the following monomer units: CH2=CH-CH3, CH2=CH-CH2-CH3, and CH2=CH-CH2-CH2-CH3. The molar mass of the repeating unit is 56.11 g/mol. What is the molar mass of the polymer with a degree of polymerization of 500?
A. 28055.0 g/mol
Correct B. 28105.0 g/mol
C. 28255.0 g/mol
D. 28305.0 g/mol

Correct Answer: B

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Question 7
A 2.50 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 8
A 50.0 mL sample of 0.100 M NaOH is mixed with a 50.0 mL sample of 0.100 M HCl. What is the pH of the resulting solution?
Correct A. 7.00
B. 8.00
C. 9.00
D. 10.00

Correct Answer: A

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Question 9
A 1.00 M solution of H2SO4 is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 10
A 2.00 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
A. 1.00
Correct B. 2.00
C. 3.00
D. 4.00

Correct Answer: B

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Question 11
The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). If 25.0 cm3 of 0.100 M CuSO4(aq) is mixed with 25.0 cm3 of 0.100 M Zn(NO3)2(aq), calculate the number of moles of Cu(s) deposited at the cathode.
A. 0.005 mol
Correct B. 0.010 mol
C. 0.015 mol
D. 0.020 mol

Correct Answer: B

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Question 12
A 10.0 cm3 sample of a solution containing 0.100 M K2Cr2O7 is mixed with 20.0 cm3 of 0.100 M H2SO4. Calculate the concentration of Cr3+ ions in the resulting solution.
A. 0.0025 M
Correct B. 0.0050 M
C. 0.0075 M
D. 0.010 M

Correct Answer: B

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Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C(s) at 298 K.
Correct A. -393.5 kJ/mol
B. -393.0 kJ/mol
C. -392.5 kJ/mol
D. -392.0 kJ/mol

Correct Answer: A

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Question 14
A 25.0 cm3 sample of a solution containing 0.100 M NaOH is mixed with 25.0 cm3 of 0.100 M HCl. Calculate the concentration of Na+ ions in the resulting solution.
A. 0.005 M
Correct B. 0.010 M
C. 0.015 M
D. 0.020 M

Correct Answer: B

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Question 15
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of vaporization of 1.00 mol of H2O(l) at 298 K.
Correct A. -40.7 kJ/mol
B. -41.2 kJ/mol
C. -41.7 kJ/mol
D. -42.2 kJ/mol

Correct Answer: A

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Question 16
Determine the number of moles of CO2 produced when 2.5 g of calcium carbonate (CaCO3) is completely decomposed at 25°C and 1 atm. The reaction is: CaCO3(s) → CaO(s) + CO2(g). The molar mass of CaCO3 is 100.09 g/mol.
A. 0.025 mol
Correct B. 0.050 mol
C. 0.075 mol
D. 0.100 mol

Correct Answer: B

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Question 17
A 2.5 L flask contains a gas at 25°C and 1 atm. If 1.5 L of the gas is removed, what is the new pressure of the gas in the flask?
A. 0.5 atm
Correct B. 0.75 atm
C. 1.0 atm
D. 1.5 atm

Correct Answer: B

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Question 18
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 1
B. 2
Correct C. 3
D. 4

Correct Answer: C

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Question 19
A 2.5 L flask contains a gas at 25°C and 1 atm. If 1.5 L of the gas is removed, what is the new pressure of the gas in the flask?
A. 0.5 atm
Correct B. 0.75 atm
C. 1.0 atm
D. 1.5 atm

Correct Answer: B

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Question 20
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 1
B. 2
Correct C. 3
D. 4

Correct Answer: C

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Question 21
Determine the molar solubility of AgCl in a 0.1 M NaCl solution, given that the solubility product cons\tant (Ksp) for AgCl is 1.8 x 10^-10.
A. 1.0 x 10^-5 M
B. 5.0 x 10^-6 M
Correct C. 1.5 x 10^-5 M
D. 2.0 x 10^-5 M

Correct Answer: C

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Question 22
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 2.00
Correct B. 3.00
C. 4.00
D. 5.00

Correct Answer: B

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Question 23
The reaction between H2S and O2 is given by the equation: 2H2S + 3O2 → 2H2O + 2SO3. Calculate the volume of O2 required to react with 2.50 L of H2S at STP.
A. 1.50 L
Correct B. 2.25 L
C. 3.00 L
D. 4.50 L

Correct Answer: B

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Question 24
A 1.00 M solution of CH3OH is prepared by dissolving 18.0 g of CH3OH in 100.0 mL of water. Calculate the mole \fraction of CH3OH in the solution.
A. 0.100
Correct B. 0.200
C. 0.300
D. 0.400

Correct Answer: B

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Question 25
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C6H12O6.
A. -2815 kJ
Correct B. -2835 kJ
C. -2855 kJ
D. -2875 kJ

Correct Answer: B

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