POST UTME JOSEPH AYO BABALOLA UNIVERSITY 2019 Chemistry | Objective

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Question 1
A 2.0 M solution of H2SO4 is prepared by dissolving 2.0 g of H2SO4 in 100 mL of water. What is the concentration of H+ ions in this solution?
A. 1.00 M
B. 2.00 M
C. 3.00 M
D. 4.00 M
Question 2
A sample of CO2 gas is collected over water at 25°C and 1 atm. If the partial pressure of CO2 is 0.5 atm, what is the mole \fraction of CO2 in the gas mixture?
A. 0.33
B. 0.5
C. 0.67
D. 0.75
Question 3
A 2.0 L flask contains 0.5 mol of CO2 at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.
A. 101.3 kPa
B. 102.1 kPa
C. 103.0 kPa
D. 104.0 kPa
Question 4
A 2.50 M solution of sodium chloride is prepared by dissolving 75.0 g of sodium chloride in 250.0 mL of water. What is the molarity of the solution?
A. 0.30 M
B. 0.50 M
C. 0.75 M
D. 1.00 M
Question 5
The half-life of a radioactive subs\tance is 5.0 years. If 100 g of the subs\tance initially contains 50 g of the radioactive isotope, how much of the isotope will remain after 10 years?
A. 25 g
B. 50 g
C. 75 g
D. 100 g
Question 6
Calculate the molar concentration of a solution containing 25.0 g of NaCl in 250 mL of water. The molar mass of NaCl is 58.44 g/mol.
A. 0.50 M
B. 0.75 M
C. 1.00 M
D. 1.25 M
Question 7
A sample of air contains 21% O2, 78% N2, and 1% other gases. Calculate the partial pressure of O2 at a total pressure of 101.3 kPa.
A. 21.3 kPa
B. 21.7 kPa
C. 22.1 kPa
D. 22.5 kPa
Question 8
A solution of sodium chloride (NaCl) is prepared by dissolving 35.5 g of NaCl in 250 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 9
A 0.500 M solution of HCl is mixed with a 0.750 M solution of NaOH. What is the concentration of the resulting solution?
A. 0.625 M
B. 0.750 M
C. 0.875 M
D. 1.125 M
Question 10
A 10.0 g sample of a polymer is dissolved in 100.0 mL of solvent. If the density of the solution is 1.2 g/mL, what is the molar mass of the polymer?
A. 1000 g/mol
B. 2000 g/mol
C. 5000 g/mol
D. 10000 g/mol
Question 11
A 0.1 M solution of HCl is titrated with a 0.1 M solution of NaOH. Calculate the number of moles of HCl that have reacted after 25 mL of NaOH has been added.
A. 0.005 mol
B. 0.010 mol
C. 0.015 mol
D. 0.020 mol
Question 12
Determine the s\tandard Gibbs free energy change for the reaction: 2Ag+(aq) + 2Cl-(aq) → Ag2Cl2(s). Given that ΔH° = -120 kJ/mol and ΔS° = 0.25 kJ/mol·K.
A. -120 kJ/mol
B. -240 kJ/mol
C. -300 kJ/mol
D. -360 kJ/mol
Question 13
A 2.0 L flask contains 0.5 mol of an ideal gas at a temperature of 298 K. What is the pressure of the gas, assuming it behaves ideally?
A. 1.0 atm
B. 2.0 atm
C. 3.0 atm
D. 4.0 atm
Question 14
A solution contains 0.50 M NaCl. What is the concentration of Cl- ions?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.00 M
Question 15
Calculate the s\tandard enthalpy change for the reaction: 2Al(s) + 3H2O(l) → 2Al(OH)3(s) + 3/2H2(g).
A. -1720 kJ/mol
B. -1850 kJ/mol
C. -1780 kJ/mol
D. -1800 kJ/mol

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