POST UTME UNILORIN 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A diagram of a gas apparatus is shown below. If the pressure of the gas is 2.0atm and the volume is 10.0L, calculate the number of moles of gas present.
A. 0.2mol
B. 0.4mol
C. 0.6mol
D. 0.8mol
Question 2
A 0.1 M solution of 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
C. 3
D. 4
Question 3
Determine the pH of a 0.1 M solution of HCl at 25°C, given that the dissociation cons\tant of HCl is 10^\( -7 \).
A. 1
B. 2
C. 3
D. 4
Question 4
A metal alloy is composed of 60% copper (Cu), 20% zinc (Zn), and 20% tin (Sn). If 500 g of the alloy is melted and cast into a new shape, what is the mass of Cu in the new shape?
A. 300 g
B. 200 g
C. 250 g
D. 350 g
Question 5
A 2.5 L flask contains 0.15 mol of CO2 at 25°C. Calculate the partial pressure of CO2 in the flask.
A. 0.75 atm
B. 0.75 atm
C. 0.75 atm
D. 0.75 atm
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) u\sing the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. -1206.5 kJ/mol
B. -1206.5 kJ/mol
C. -1206.5 kJ/mol
D. -1206.5 kJ/mol
Question 7
A 1.0 M solution of a salt Na2SO4 is prepared by dissolving 58.44 g of Na2SO4 in 1 L of water. What is the molarity of the sulfate ion \( SO42- \) in the solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M
Question 8
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 9
A 2.5 L flask contains 0.5 mol of an ideal gas at 25°C. Calculate the pressure of the gas.
A. 1 atm
B. 2 atm
C. 3 atm
D. 4 atm
Question 10
A 1.0g sample of a metal is heated to a cons\tant mass. If 0.5g of the metal oxide is obtained, calculate the percentage yield of the metal oxide.
A. 50%
B. 60%
C. 70%
D. 80%
Question 11
A 1.0 L flask contains 0.2 mol of an ideal gas at 50°C. Calculate the pressure of the gas.
A. 1 atm
B. 2 atm
C. 3 atm
D. 4 atm
Question 12
A metal M \( atomic mass 50 g/mol \) reacts with chlorine gas to form a compound MCl2. If 2.5 g of M is reacted with 10 mL of Cl2, what is the volume of Cl2 gas consumed?
A. 10 mL
B. 20 mL
C. 30 mL
D. 40 mL
Question 13
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 14
A polymer has a molecular weight of 5000 g/mol and a degree of polymerization of 100. What is the molar mass of the repeating unit?
A. 50 g/mol
B. 100 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 15
A diagram of a titration setup is shown below. What is the purpose of the burette in this setup?
A. To measure the volume of the solution
B. To measure the pH of the solution
C. To mix the solutions
D. To filter the solution

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