POST UTME SKYLINE UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of a metal oxide is heated in a crucible until it reaches a temperature of 1000°C. If the mass of the oxide is 50 g, what is the mass of the metal that is produced?
A. 20 g
B. 25 g
C. 30 g
D. 40 g
Question 2
A gas at 25°C and 1 atm is compressed to 2 atm. If the initial volume is 2.00 L, what is the final volume?
A. 1.00 L
B. 1.50 L
C. 2.00 L
D. 2.50 L
Question 3
A solution of HCl is titrated with NaOH. If 25 mL of 1 M HCl is required to reach the equivalence point, what is the concentration of the NaOH solution?
A. 0.5 M
B. 1 M
C. 2 M
D. 5 M
Question 4
The diagram below shows a chemical apparatus setup.
A. \( HCl + NaOH \rightarrow NaCl + H_2O \)
B. \( H_2SO_4 + NaOH \rightarrow Na_2SO_4 + H_2O \)
C. \( HNO_3 + NaOH \rightarrow NaNO_3 + H_2O \)
D. \( H_3PO_4 + NaOH \rightarrow Na_3PO_4 + H_2O \)
Question 5
The sulfur cycle is an impor\tant environmental chemistry process. Which of the following is a key step in the sulfur cycle?
A. \( SO_2 + H_2O \rightarrow H_2SO_4 \)
B. \( SO_2 + O_2 \rightarrow SO_3 \)
C. \( SO_2 + H_2O \rightarrow H_2S \)
D. \( SO_2 + O_2 \rightarrow SO_4^{2-} \)
Question 6
A sample of CO2 gas is collected over water at a temperature of 25°C and a pressure of 1 atm. If the partial pressure of CO2 is 0.5 atm, what is the mole \fraction of CO2 in the gas mixture?
A. 0.2
B. 0.5
C. 0.8
D. 1.0
Question 7
A 0.500 M solution of HCl is titrated with 0.500 M NaOH. If 25.0 mL of NaOH is required to reach the equivalence point, what is the pH of the solution at this point?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 8
A 1.00 M solution of H2SO4 is titrated with 1.00 M NaOH. If 20.0 mL of NaOH is required to reach the equivalence point, what is the pH of the solution at this point?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 9
The reaction of nitrogen dioxide with water is a classic example of an environmental chemistry process. Which of the following is the correct equation for this reaction?
A. \( 2NO_2 + H_2O \rightarrow HNO_3 + NO \)
B. \( 2NO_2 + H_2O \rightarrow HNO_3 + HNO_2 \)
C. \( 2NO_2 + H_2O \rightarrow HNO_3 + O_2 \)
D. \( 2NO_2 + H_2O \rightarrow HNO_3 + NO_2 \)
Question 10
A mixture of 25.0 g of NaCl and 15.0 g of KCl is dissolved in 250 cm3 of water. What is the molarity of the solution?
A. 0.100 M
B. 0.200 M
C. 0.500 M
D. 1.00 M
Question 11
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 12
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 titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To separate the titrant and analyte
Question 13
A polymer is composed of repeating units called monomers. If a polymer has a molecular weight of 100,000 g/mol and is composed of 500 monomers, what is the average molecular weight of each monomer?
A. 150
B. 200
C. 250
D. 300
Question 14
A solution of NaCl is prepared by dissolving 35.5 g of NaCl in 250 cm3 of water. What is the molarity of the solution?
A. 0.100 M
B. 0.200 M
C. 0.500 M
D. 1.00 M
Question 15
A sample of a non-metallic element has a mass of 25.0 g and a volume of 5.00 cm3. What is the density of the element?
A. 2.50 g/cm3
B. 5.00 g/cm3
C. 10.0 g/cm3
D. 25.0 g/cm3

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