POST UTME UNN 2022 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The atomic radius of a metal atom is 200 pm. If the metal atom has a valency of 2, what is the expected value of the atomic radius of its monovalent ion?
A. 180 pm
B. 220 pm
C. 240 pm
D. 260 pm
Question 2
A sample of nitrogen gas at 25°C and 1 atm is allowed to expand into a larger container. If the final temperature is 50°C and the final pressure is 0.5 atm, what is the final volume of the gas?
A. 0.25 m³
B. 0.5 m³
C. 1 m³
D. 2 m³
Question 3
A 2.5 L flask contains 0.5 mol of an ideal gas at 300 K. If the gas is heated to 400 K at cons\tant volume, what is the new pressure?
A. 1.5 atm
B. 2.5 atm
C. 3.5 atm
D. 4.5 atm
Question 4
A polymer has a degree of polymerization (n) of 1000. If the molecular weight of the repeating unit is 100 g/mol, what is the molecular weight of the polymer?
A. 100,000 g/mol
B. 200,000 g/mol
C. 300,000 g/mol
D. 400,000 g/mol
Question 5
A 1.0 M solution of NaOH is mixed with a 2.0 M solution of HCl. What is the concentration of the resulting solution?
A. 1.0 M
B. 1.5 M
C. 2.0 M
D. 2.5 M
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 10.0 mL sample of a 0.100 M solution of NaOH is mixed with 10.0 mL of a 0.100 M solution of HCl. What is the pH of the resulting solution?
A. 7.00
B. 7.00
C. 7.00
D. 7.00
Question 8
A 2.5 M solution of HCl is mixed with a 1.5 M solution of NaOH. What is the concentration of the resulting solution?
A. 1.5 M
B. 2.5 M
C. 3.5 M
D. 4.5 M
Question 9
A 10 g sample of a subs\tance is burned in a bomb calorimeter, relea\sing 2500 J of heat. If the heat capacity of the calorimeter is 1000 J/K, what is the change in internal energy (ΔU) of the subs\tance?
A. -2500 J
B. -2000 J
C. -1500 J
D. -1000 J
Question 10
The solubility of a gas in a liquid is influenced by the following factors: temperature, pressure, and the nature of the gas and liquid. Which of the following statements is NOT true about the solubility of a gas in a liquid?
A. The solubility of a gas in a liquid increases with increa\sing temperature.
B. The solubility of a gas in a liquid decreases with increa\sing pressure.
C. The solubility of a gas in a liquid is indep\endent of the nature of the gas and liquid.
D. The solubility of a gas in a liquid increases with increa\sing pressure.
Question 11
A 0.1 M solution of a weak acid HA is 5% ionized at 25°C. Calculate the pH of the solution.
A. 2.3
B. 2.5
C. 2.7
D. 2.9
Question 12
A metal has a density of 10 g/cm³. If the metal has a volume of 2 cm³, what is the expected mass of the metal?
A. 20 g
B. 30 g
C. 40 g
D. 50 g
Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 14
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 15
The reaction between chlorine gas and potassium iodide is a classic example of a redox reaction. Write the balanced chemical equation for this reaction, including the states of matter for each reac\tant and product.
A. Cl2(g) + 2KI(s) → 2KCl(s) + I2(s)
B. Cl2(g) + 2KI(s) → 2KCl(s) + I2(g)
C. Cl2(g) + 2KI(l) → 2KCl(l) + I2(g)
D. Cl2(l) + 2KI(s) → 2KCl(s) + I2(g)

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