POST UTME RHEMA UNIVERSITY 2022 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 1.8 g. Calculate the percentage yield of the metal oxide.
A. 72%
B. 80%
C. 90%
D. 95%
Question 2
A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: 2X + Cl_2 → 2XCl. If 2.5 g of X reacts with 1.5 g of Cl_2, what is the percentage yield of the reaction?
A. 80%
B. 90%
C. 95%
D. 98%
Question 3
The rate cons\tant (k) for a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the rate cons\tant at 25°C is 0.05 s^\( -1 \) and at 50°C is 0.15 s^\( -1 \), calculate the activation energy (Ea) of the reaction in kJ/mol.
A. 20 kJ/mol
B. 30 kJ/mol
C. 40 kJ/mol
D. 50 kJ/mol
Question 4
A gas at 300 K is heated to 500 K. If the initial volume is 2.5 L, what is the final volume if the gas is ideal?
A. 5.0 L
B. 10.0 L
C. 2.5 L
D. 1.25 L
Question 5
A 2.50 L flask contains 0.250 mol of an ideal gas at 298 K. Calculate the pressure of the gas.
A. 1.01 x 10^5 Pa
B. 2.01 x 10^5 Pa
C. 3.01 x 10^5 Pa
D. 4.01 x 10^5 Pa
Question 6
A 2.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, calculate the partial pressure of the gas.
A. 0.97 atm
B. 1.00 atm
C. 1.03 atm
D. 1.07 atm
Question 7
A 1.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of the gas?
A. 0.976 atm
B. 1.00 atm
C. 1.02 atm
D. 1.04 atm
Question 8
A 1 M solution of a strong acid is prepared by dissolving 36.5 g of the acid in 1 dm^3 of water. If the density of the acid is 1.2 g/cm^3, what is the molar mass of the acid?
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 9
Determine the number of unpaired electrons in the ground state of a neutral atom of the element with atomic number 13.
A. 4
B. 2
C. 6
D. 8
Question 10
A 2.00 L flask contains 0.200 mol of O2 at 298 K. Calculate the mole \fraction of O2.
A. 0.100
B. 0.200
C. 0.300
D. 0.400
Question 11
A 10% solution of a polymer is prepared by dissolving 10 g of the polymer in 90 g of a solvent. If the density of the polymer is 1.2 g/cm^3, what is the volume of the polymer in the solution?
A. 8.3 cm^3
B. 10 cm^3
C. 12 cm^3
D. 15 cm^3
Question 12
A 2.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, calculate the mole \fraction of the gas.
A. 0.95
B. 0.98
C. 0.99
D. 1.00
Question 13
A 2.50 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 2.00 g. What is the percentage yield of the metal oxide?
A. 80.0%
B. 90.0%
C. 95.0%
D. 98.0%
Question 14
A 2.50 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 1.75 g, calculate the percentage yield of the metal oxide.
A. 85.0%
B. 90.0%
C. 92.5%
D. 95.0%
Question 15
A 2.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of the gas?
A. 0.976 atm
B. 1.00 atm
C. 1.02 atm
D. 1.04 atm

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: