POST UTME ELIZADE UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A cell has a potential difference of 1.5 V and a resis\tance of 10 Ω. What is the current flowing through the cell?
A. 0.15 A
B. 0.3 A
C. 0.45 A
D. 0.6 A
Question 2
A solution contains 0.01 M HCl and 0.01 M NaOH. What is the pH of the solution after mixing?
A. 7
B. 6
C. 5
D. 4
Question 3
A 2.5 M solution of NaOH is mixed with a 1.5 M solution of HCl. Calculate the pH of the resulting solution.
A. 1
B. 2
C. 3
D. 4
Question 4
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of formation of CH4(g) u\sing Hess's law.
A. -74.8 kJ/mol
B. -74.2 kJ/mol
C. -75.1 kJ/mol
D. -75.5 kJ/mol
Question 5
A 2.5 M solution of HCl is titrated with a 1.0 M solution of NaOH. If 25 mL of NaOH is required to reach the equivalence point, what is the volume of HCl required?
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 6
A solution contains 0.5 M NaCl and 0.2 M CaCl2. What is the concentration of Cl- ions?
A. 0.3 M
B. 0.5 M
C. 0.7 M
D. 0.9 M
Question 7
A gas at 300 K and 1 atm is compressed to 2 atm. Calculate the new volume of the gas, assuming ideal behavior.
A. 0.5 L
B. 1 L
C. 2 L
D. 4 L
Question 8
The half-life of a radioactive subs\tance is 5 days. If 100 mg of the subs\tance is initially present, how much of the subs\tance will remain after 15 days?
A. 12.5 mg
B. 25 mg
C. 50 mg
D. 100 mg
Question 9
A solution contains 0.5 M NaOH and 0.5 M HCl. Calculate the pH of the solution.
A. 0
B. 1
C. 2
D. 3
Question 10
A diagram of a titration setup is shown below. If 25.0 mL of 0.1 M NaOH is added to 25.0 mL of 0.1 M HCl, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 11
A polymer has a molecular weight of 100,000 g/mol. If 1 g of the polymer is dissolved in 100 mL of water, what is the concentration of the solution in g/L?
A. 1 g/L
B. 10 g/L
C. 100 g/L
D. 1000 g/L
Question 12
The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100 g, what is the amount remaining after 10 years?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g
Question 13
The reaction 2Al(s) + Fe2O3(s) → Al2O3(s) + 2Fe(s) is a redox reaction. Identify the oxidizing agent.
A. Al
B. Fe2O3
C. Al2O3
D. Fe
Question 14
The reaction 2H2(g) + O2(g) → 2H2O(l) is an example of a _______________ reaction.
A. synthesis
B. decomposition
C. \single displacement
D. combustion
Question 15
At 273 K, the root mean square speed of a gas is 200 m/s. What is the temperature at which the root mean square speed is 400 m/s?
A. 373 K
B. 473 K
C. 573 K
D. 673 K

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