POST UTME GREENFIELD UNIVERSITY 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A mixture of 10 g of NaCl and 20 g of KCl is dissolved in water to make 1 L of solution. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 2
A 25 mL sample of a polymer solution containing 0.5 g/mL of polyethylene oxide (PEO) is dissolved in 75 mL of water. Calculate the number-average molecular weight of the PEO.
A. 1000
B. 2000
C. 3000
D. 4000
Question 3
A 2.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in water to make 1 L of solution. What is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 4
Calculate the s\tandard enthalpy of formation of CO2(g) from the following data: ΔH°f(CO2(g)) = -393.5 kJ/mol, ΔH°f(C) = 0 kJ/mol, ΔH°f(O2(g)) = 0 kJ/mol.
A. -393.5 kJ/mol
B. -393.5 kJ/mol + 0 kJ/mol + 0 kJ/mol
C. -393.5 kJ/mol - 0 kJ/mol - 0 kJ/mol
D. -393.5 kJ/mol + 0 kJ/mol
Question 5
A metal is extracted from its ore u\sing a reduction reaction. The ore is first roasted to convert it into a more reactive form. What is the purpose of roasting the ore?
A. To increase the reactivity of the ore
B. To decrease the reactivity of the ore
C. To convert the ore into a more stable form
D. To remove impurities from the ore
Question 6
Determine the pH of a 0.1 M solution of HCl after 10 mL of 1 M NaOH has been added to 20 mL of the HCl solution.
A. 2
B. 3
C. 4
D. 5
Question 7
A 0.1 M solution of HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, what is the volume of the HCl solution?
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 8
Determine the number of moles of oxygen gas (O2) required to completely combust 2.5 moles of propane (C3H8) according to the balanced equation: C3H8 + 5O2 → 3CO2 + 4H2O.
A. 1.25
B. 2.5
C. 5
D. 10
Question 9
A 2.5 M solution of sodium hydroxide (NaOH) is electrolyzed u\sing a platinum electrode. If the electrolysis is carried out for 2 hours, and the current is 5 A, what is the mass of hydrogen gas (H2) produced at the cathode?
A. 0.5 g
B. 1 g
C. 2 g
D. 4 g
Question 10
A 1.0 M solution of HCl is prepared by dissolving 36.5 g of HCl in water to make 1 L of solution. What is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 11
A polymer is formed by the condensation reaction between two monomers, A and B. If the molecular weight of the polymer is 100,000 g/mol, and the molecular weights of the monomers are 20,000 g/mol and 30,000 g/mol, respectively, what is the average degree of polymerization?
A. 2
B. 3
C. 4
D. 5
Question 12
A 2.5 M solution of NaOH is prepared by dissolving 25 g of NaOH in water to make 1 L of solution. What is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 2.5 M
D. 3.0 M
Question 13
A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 14
A 1.0 L flask contains 0.5 mol of an ideal gas at a temperature of 300 K. If the gas is compressed to 0.5 L at cons\tant temperature, what is the new pressure of the gas?
A. 2.0 atm
B. 3.0 atm
C. 4.0 atm
D. 5.0 atm
Question 15
A sample of a non-metallic solid is heated in a crucible until it melts. The resulting liquid has a boiling point of 100°C. What is the identity of the non-metallic solid?
A. Sulfur
B. Phosphorus
C. Arsenic
D. Antimony

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