POST UTME RSU 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of CO2 is collected over water at a temperature of 25°C and a pressure of 1 atm. What is the partial pressure of CO2 in the gas mixture?
A. \( P_{CO_2} = P_{total} - P_{H_2O} \)
B. \( P_{CO_2} = P_{total} + P_{H_2O} \)
C. \( P_{CO_2} = P_{total} \times P_{H_2O} \)
D. \( P_{CO_2} = P_{total} div P_{H_2O} \)
Question 2
A 0.1 M solution of NaOH is mixed with a 0.1 M solution of HCl. If the initial volume of each solution is 100 mL, what is the pH of the resulting solution after the reaction is complete?
A. 1
B. 2
C. 3
D. 4
Question 3
The diagram below shows a chemical apparatus setup. What is the purpose of the filter paper?
A. to separate the solid from the liquid
B. to mix the solid with the liquid
C. to heat the liquid
D. to cool the liquid
Question 4
A 0.5 mol sample of CO2 is placed in a 1 L flask at 25°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 101325 Pa
B. 202650 Pa
C. 303875 Pa
D. 405100 Pa
Question 5
A metal has an atomic radius of 100 pm and a metallic radius of 250 pm. What is the percentage increase in the metallic radius compared to the atomic radius?
A. 50%
B. 60%
C. 70%
D. 80%
Question 6
A solution of HCl is electrolyzed u\sing a platinum electrode. The reaction at the anode is 2H2O → O2 + 4H+ + 4e-.
A. 2H2O → O2 + 4H+ + 4e-
B. 2H2O → 2H2 + O2
C. 2H2O → H2 + 2OH-
D. 2H2O → H2O2 + 2H+
Question 7
A 2.0 L flask contains 0.5 mol of an ideal gas at 25°C. If the gas is heated to 100°C, what is the new volume of the gas?
A. 4.0 L
B. 6.0 L
C. 8.0 L
D. 10.0 L
Question 8
Determine the molar mass of a polymer with the following composition: 60% polyethylene (C2H4), 20% polypropylene (C3H6), and 20% polystyrene (C8H8).
A. 60 g/mol
B. 120 g/mol
C. 180 g/mol
D. 240 g/mol
Question 9
The diagram below shows a chemical reaction. What is the type of reaction?
A. synthesis reaction
B. decomposition reaction
C. replacement reaction
D. combustion reaction
Question 10
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of C(s) + O2(g) → CO2(g).
A. -393.5 kJ/mol
B. -393.5 kJ/mol + 0 kJ/mol
C. -393.5 kJ/mol - 0 kJ/mol
D. 0 kJ/mol
Question 11
The diagram below shows a titration setup. What is the purpose of the burette?
A. to measure the volume of the titrant
B. to measure the volume of the analyte
C. to mix the titrant and analyte
D. to separate the titrant and analyte
Question 12
The bond order of a molecule is determined by
A. number of electrons in bonding orbitals
B. number of electrons in antibonding orbitals
C. number of electrons in molecular orbitals
D. number of electrons in atomic orbitals
Question 13
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. Calculate the number of moles of nitrogen gas present.
A. 0.2 mol
B. 0.5 mol
C. 1.0 mol
D. 2.0 mol
Question 14
A 2.0 M solution of NaOH is titrated with 1.0 M HCl. What is the pH of the solution after 20 mL of HCl has been added?
A. \( pH = \frac{1}{2} \log \frac{[NaOH]}{[HCl]} \)
B. \( pH = \frac{1}{2} \log \frac{[HCl]}{[NaOH]} \)
C. \( pH = \frac{1}{2} \log \frac{[NaOH] + [HCl]}{[NaOH]} \)
D. \( pH = \frac{1}{2} \log \frac{[HCl]}{[NaOH] + [HCl]} \)
Question 15
A sample of sulfur dioxide gas occupies a volume of 3.2 L at a pressure of 2.0 atm and a temperature of 300 K. Calculate the number of moles of sulfur dioxide gas present.
A. 0.3 mol
B. 0.6 mol
C. 1.2 mol
D. 2.4 mol

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