POST UTME ELIZADE UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.50 g sample of a gas at 25°C and 1.00 atm is collected over water at 25°C. If the vapor pressure of water at 25°C is 23.8 mmHg, calculate the partial pressure of the gas.
A. 1.72 atm
B. 1.73 atm
C. 1.74 atm
D. 1.75 atm
Question 2
The diagram below represents a titration setup. Identify the part labeled A.
A. Burette
B. Beaker
C. Conical flask
D. Pipette
Question 3
A solution of 10 g of glu\cose in 100 mL of water has a boiling point elevation of 0.5°C. What is the molar mass of glu\cose?
A. 180 g/mol
B. 200 g/mol
C. 220 g/mol
D. 240 g/mol
Question 4
A 1.00 L flask contains 0.100 M NaCl. What is the concentration of Cl- ions in the solution?
A. 0.100 M
B. 0.0500 M
C. 0.0250 M
D. 0.0125 M
Question 5
A 0.1 M solution of NaOH is prepared by dissolving 4 g of NaOH in 100 mL of water. Calculate the molarity of the solution.
A. 0.2 M
B. 0.1 M
C. 0.05 M
D. 0.01 M
Question 6
The molar mass of a compound is 180 g/mol. If 10 g of the compound is dissolved in 100 mL of water, what is the concentration of the solution in g/L?
A. 1.8 g/L
B. 18 g/L
C. 180 g/L
D. 1800 g/L
Question 7
A sample of a gas occupies a volume of 2.5 L at a pressure of 3.0 atm and a temperature of 298 K. What is the new volume of the gas if the pressure is increased to 4.0 atm and the temperature is decreased to 273 K?
A. 1.5 L
B. 2.0 L
C. 2.5 L
D. 3.0 L
Question 8
A sample of a polymer has a molecular weight of 50,000 g/mol. What is the number of monomer units in the polymer?
A. 250 units
B. 500 units
C. 750 units
D. 1000 units
Question 9
A 2.00 M solution of NaOH is mixed with a 2.00 M solution of HCl. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 10
Determine the type of bond present in the molecule H2S.
A. Sigma (σ) bond
B. Pi (π) bond
C. Sigma (σ) and Pi (π) bond
D. Hydrogen bond
Question 11
The diagram below represents a chemical apparatus setup. Identify the part labeled B.
A. Test tube
B. Burette
C. Conical flask
D. Pipette
Question 12
A 2.00 g sample of a subs\tance is found to have a mass of 2.50 g after being heated in a furnace at 1000°C for 1 hour. What is the percentage increase in mass?
A. 25.0%
B. 26.0%
C. 27.0%
D. 28.0%
Question 13
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. -393.0 kJ/mol
C. -392.5 kJ/mol
D. -392.0 kJ/mol
Question 14
A colloidal solution of starch in water has a Tyndall effect. What is the reason for this phenomenon?
A. The particles in the solution are too small to scatter light.
B. The particles in the solution are too large to scatter light.
C. The particles in the solution are in a state of Brownian motion.
D. The particles in the solution are in a state of thermal motion.
Question 15
A mixture of gases is composed of 20% helium, 30% oxygen, and 50% nitrogen by volume. If the total pressure of the mixture is 2.5 atm, what is the partial pressure of helium?
A. 0.5 atm
B. 1.0 atm
C. 1.25 atm
D. 1.5 atm

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