POST UTME ELIZADE UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2 M solution of a salt (Na2SO4) is prepared by dissolving 2 g of the salt in 100 mL of water. What is the molarity of the solution?
A. 1 M
B. 2 M
C. 3 M
D. 4 M
Question 2
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. If 20 mL of HCl is required to reach the equivalence point, what is the volume of NaOH required to reach the equivalence point in a 50 mL solution?
A. 50 mL
B. 100 mL
C. 150 mL
D. 200 mL
Question 3
A metal (X) reacts with oxygen to form a basic oxide. The oxide is soluble in water and gives a basic solution. The metal (X) is likely to be:
A. Al
B. Mg
C. Ca
D. Na
Question 4
A sample of CO2 is collected over water at 25°C and 1 atm. If the partial pressure of CO2 is 0.75 atm, what is the mole \fraction of CO2 in the gas mixture?
A. 0.60
B. 0.65
C. 0.70
D. 0.75
Question 5
A diagram of a titration setup is shown below. If 25 mL of 0.5 M NaOH is added to 25 mL of 0.5 M HCl, what is the pH of the resulting solution?
A. 0.1
B. 1
C. 2
D. 3
Question 6
Determine the number of moles of CO2 produced when 2.50 g of calcium carbonate (CaCO3) is heated in a stream of oxygen gas.
A. 0.0250 mol
B. 0.0500 mol
C. 0.0750 mol
D. 0.100 mol
Question 7
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 8
Determine the number of stereoisomers for the compound 2,3-dimethylpen\tane.
A. 1
B. 2
C. 3
D. 4
Question 9
A metal oxide has the formula M2O3. If 2.5 g of the oxide is dissolved in acid to produce 0.5 mol of hydrogen gas, calculate the molar mass of the metal.
A. 50 g/mol
B. 60 g/mol
C. 70 g/mol
D. 80 g/mol
Question 10
Calculate the pH of a 0.1 M solution of HCl.
A. 0.1
B. 1
C. 2
D. 3
Question 11
A solution of 0.5M HCl is titrated with 0.5M NaOH. What is the pH of the solution after 25mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 12
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CaCO3(s)?
A. -120.3 kJ/mol
B. -180.3 kJ/mol
C. -240.3 kJ/mol
D. -300.3 kJ/mol
Question 13
A solution contains 0.1 M HCl and 0.1 M NaOH. Calculate the pH of the solution after 20 mL of 1 M HCl has been added to 100 mL of the solution.
A. 1
B. 2
C. 3
D. 4
Question 14
The s\tandard electrode potential of the Zn2+/Zn couple is -0.76 V. Calculate the s\tandard electrode potential of the Cu2+/Cu couple if the s\tandard electrode potential of the Cu2+/Cu couple is +0.34 V.
A. +0.10 V
B. +0.20 V
C. +0.30 V
D. +0.40 V
Question 15
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the addition of 15.0 mL of NaOH?
A. 2.00
B. 3.00
C. 4.00
D. 5.00

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