POST UTME NILE UNIVERSITY 2019 Chemistry | Objective

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Question 1
A 2.5 g sample of a subs\tance is dissolved in 100 mL of water. If the molarity of the solution is 0.5 M, what is the molar mass of the subs\tance?
A. 50 g/mol
B. 100 g/mol
C. 150 g/mol
D. 200 g/mol
Question 2
A polymer is composed of 80% polyethylene and 20% polypropylene. If the density of polyethylene is 0.95 g/cm3 and the density of polypropylene is 0.90 g/cm3, what is the average density of the polymer?
A. 0.88 g/cm3
B. 0.92 g/cm3
C. 0.96 g/cm3
D. 1.00 g/cm3
Question 3
A 0.500 M solution of NaOH is prepared by dissolving 25.0 g of NaOH in 100.0 mL of water. What is the pH of the solution?
A. 12.0
B. 13.0
C. 14.0
D. 15.0
Question 4
A 2.0 L sample of H2O contains 1.0 g of NaCl. What is the concentration of NaCl in the solution?
A. 0.5 g/L
B. 1.0 g/L
C. 1.5 g/L
D. 2.0 g/L
Question 5
A 1.00 L flask contains 0.100 M H2(g) and 0.100 M O2(g). If the reaction is allowed to proceed until equilibrium is reached, what is the concentration of H2O(g)?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 6
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. What is the pH of the solution after 50 mL of HCl has been added?
A. 1
B. 2
C. 3
D. 4
Question 7
Determine the s\tandard enthalpy of formation of NH3(g) from the following data: ΔHf(NH3(g)) = -46.1 kJ/mol, ΔHf(H2(g)) = 0 kJ/mol, ΔHf(N2(g)) = 0 kJ/mol.
A. -46.1 kJ/mol
B. -92.2 kJ/mol
C. -46.2 kJ/mol
D. -92.1 kJ/mol
Question 8
A 0.5 M solution of HCl is mixed with a 0.5 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 9
A 1.0 L sample of H2O contains 2.0 g of NaCl. What is the concentration of NaCl in the solution?
A. 1.0 g/L
B. 2.0 g/L
C. 3.0 g/L
D. 4.0 g/L
Question 10
A solution contains 2.0 g of NaCl per 100 mL of water. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 11
The half-life of a radioactive subs\tance is 5.00 years. If 100 g of the subs\tance initially exists, how much will remain after 10.0 years?
A. 12.5 g
B. 25.0 g
C. 50.0 g
D. 100 g
Question 12
A 2.50 L flask contains 0.500 M H2SO4. What is the concentration of H+ ions in the solution?
A. 0.500 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 13
A 1.5 L container is filled with a gas at 25°C and 1 atm. If the gas is compressed to 0.5 L at cons\tant temperature, what is the new pressure?
A. 2 atm
B. 3 atm
C. 4 atm
D. 5 atm
Question 14
A 1.5 L container is filled with a gas at 25°C and 1 atm. If the gas is compressed to 0.5 L at cons\tant temperature, what is the new pressure?
A. 2 atm
B. 3 atm
C. 4 atm
D. 5 atm
Question 15
A 0.5 M solution of HCl is mixed with a 0.5 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4

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