POST UTME PAN-ATLANTIC UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.0 g sample of a hydrocarbon is burned in a bomb calorimeter. The temperature of the calorimeter increases by 3.5°C. Calculate the heat of combustion of the hydrocarbon.
A. -3600 kJ/mol
B. -3700 kJ/mol
C. -3800 kJ/mol
D. -3900 kJ/mol
Question 2
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. What is its molar mass?
A. 500 g/mol
B. 1000 g/mol
C. 2000 g/mol
D. 5000 g/mol
Question 3
A 1.0 M solution of NaOH is titrated with 1.0 M HCl. Calculate the pH of the solution after 50 mL of HCl has been added.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 4
A solution of 0.100 M HCl is titrated with 0.100 M NaOH. If 25.0 mL of HCl is required to reach the equivalence point, what is the pH of the resulting solution?
A. 7.00
B. 7.50
C. 8.00
D. 9.00
Question 5
A 2.5 L flask contains 0.15 mol of an ideal gas at 27°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 2.1 atm
B. 2.2 atm
C. 2.3 atm
D. 2.4 atm
Question 6
A redox reaction involves the transfer of electrons from one species to another. Which of the following is an example of a redox reaction?
A. 2H2 + O2 → 2H2O
B. 2H2O → 2H2 + O2
C. 2H2 + O2 → 2H2O2
D. 2H2O2 → 2H2 + O2
Question 7
The reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl) is a classic example of a neutralization reaction. If 25.0 mL of 0.100 M NaOH is added to 25.0 mL of 0.100 M HCl, what is the pH of the resulting solution?
A. 7.00
B. 7.50
C. 8.00
D. 9.00
Question 8
A 2.50 g sample of an unknown hydrocarbon is burned in a combustion calorimeter. The resulting CO2 gas is collected and found to have a volume of 1.25 L at 25°C and 1 atm. What is the molar mass of the hydrocarbon?
A. 50.0 g/mol
B. 75.0 g/mol
C. 100 g/mol
D. 125 g/mol
Question 9
A 0.500 L solution of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after 25.0 mL of NaOH has been added.
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 10
A 1.00 L solution of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 50.0 mL
B. 75.0 mL
C. 100 mL
D. 125 mL
Question 11
A sample of CO2 gas is collected over water at 25°C and 1 atm. If the partial pressure of CO2 is 0.75 atm, calculate the mole \fraction of CO2 in the gas mixture.
A. 0.25
B. 0.50
C. 0.75
D. 1.00
Question 12
A 2.5 L sample of a gas at 27°C and 1 atm is collected over water. If the vapor pressure of water at 27°C is 0.0313 atm, calculate the partial pressure of the gas.
A. 0.969 atm
B. 0.98 atm
C. 0.991 atm
D. 1 atm
Question 13
A 2.50 g sample of a polymer is dissolved in 25.0 mL of a solvent. If the molar mass of the polymer is 50.0 g/mol, calculate the number of moles of polymer dissolved.
A. 0.0500 mol
B. 0.0505 mol
C. 0.0510 mol
D. 0.0515 mol
Question 14
A 2.5 M solution of H2SO4 is titrated with 1.0 M NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 15
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. Assume the reaction is: CaO(s) + CO2(g) → CaCO3(s).
A. -1207.6 kJ/mol
B. -1208.6 kJ/mol
C. -1209.6 kJ/mol
D. -1210.6 kJ/mol

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