POST UTME LEAD CITY UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.00250 mol
B. 0.00500 mol
C. 0.00750 mol
D. 0.0100 mol
Question 2
A 10 mL sample of 0.5 M NaOH is titrated with 0.1 M HCl. Calculate the pH of the solution after 20 mL of HCl has been added.
A. 1
B. 2
C. 3
D. 4
Question 3
Determine the molar mass of a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. The atomic masses of carbon, hydrogen, and oxygen are 12.01 g/mol, 1.008 g/mol, and 16.00 g/mol, respectively.
A. 120.0 g/mol
B. 140.0 g/mol
C. 160.0 g/mol
D. 180.0 g/mol
Question 4
A 1.00 L flask contains 0.500 mol of H2 and 0.250 mol of F2 at 25°C. If the reaction 2H2(g) + F2(g) → 2HF(g) is allowed to proceed until equilibrium is reached, what is the concentration of HF in the flask?
A. 0.125 M
B. 0.250 M
C. 0.375 M
D. 0.500 M
Question 5
A 25 mL sample of 0.2 M NaOH is titrated with 0.1 M HCl. Calculate the pH of the solution after 10 mL of HCl has been added.
A. 2
B. 3
C. 4
D. 5
Question 6
A 2.00 L flask contains 0.500 mol of N2 and 0.250 mol of O2 at 25°C. If the reaction 2N2(g) + O2(g) → 2N2O(g) is allowed to proceed until equilibrium is reached, what is the concentration of N2O in the flask?
A. 0.125 M
B. 0.250 M
C. 0.375 M
D. 0.500 M
Question 7
A 2.0 L flask contains 0.5 mol of CO2 at 27°C. Calculate the number of moles of O2 required to react with the CO2 according to the equation: CO2 + 1/2 O2 → CO + 1/2 O2.
A. 0.25 mol
B. 0.5 mol
C. 0.75 mol
D. 1.0 mol
Question 8
A sample of gas at 25°C and 1 atm is allowed to expand to twice its original volume. What is the new pressure of the gas?
A. 0.5 atm
B. 1 atm
C. 2 atm
D. 4 atm
Question 9
A metal M reacts with chlorine gas to form a compound MCl_2. The molar mass of MCl_2 is 142.6 g/mol. If the molar mass of chlorine is 35.5 g/mol, what is the molar mass of metal M?
A. 60.6 g/mol
B. 61.6 g/mol
C. 62.6 g/mol
D. 63.6 g/mol
Question 10
A 0.5 M solution of NaOH is prepared by dissolving 3.5 g of NaOH in 1000 mL of water. What is the molarity of the solution if 10 mL of the solution is diluted to 100 mL with water?
A. 0.3 M
B. 0.35 M
C. 0.4 M
D. 0.45 M
Question 11
A polymer is a long chain of repeating units. What is the name of the repeating unit in the polymer polyethylene?
A. Ethylene
B. Polyethylene
C. Ethane
D. Propane
Question 12
A solution of 0.1 M H2SO4 is prepared by dissolving 0.1 mol of H2SO4 in 1 L of water. Calculate the concentration of H+ ions in the solution.
A. 0.01
B. 0.1
C. 1
D. 10
Question 13
The atomic radius of an element is 100 pm. If the element is in the 3rd period of the periodic table, what is the expected value of its atomic radius in the 4th period?
A. 120 pm
B. 110 pm
C. 130 pm
D. 140 pm
Question 14
A sample of gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 300 K. What is the new volume of the gas if the pressure is increased to 3.5 atm and the temperature is decreased to 200 K?
A. 1.2 L
B. 1.5 L
C. 1.8 L
D. 2.0 L
Question 15
The compound SO2 is a toxic gas. What is the oxidation state of sulfur in this compound?
A. +2
B. -2
C. +4
D. -4

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