POST UTME SKYLINE UNIVERSITY 2019 Chemistry | Objective

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Question 1
A 0.5 M solution of sodium chloride (NaCl) is prepared by dissolving 5 g of the salt in 100 mL of water. What is the concentration of chloride ions \( Cl- \) in the solution?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1 M
Question 2
A diagram of a metal alloy is shown below. If the composition of the alloy is 75% copper and 25% zinc, calculate the mass of copper in a 100 g sample of the alloy.
A. 50 g
B. 60 g
C. 70 g
D. 80 g
Question 3
A solution contains 25.0 mL of 0.100 M HCl and 50.0 mL of 0.0500 M NaOH. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 4
A 0.05 M solution of a weak base, B, is titrated with 0.05 M HCl. At the equivalence point, the pH of the solution is 6. Calculate the pKa of the base.
A. 6
B. 10
C. 14
D. 21
Question 5
A gas occupies a volume of 2.50 L at a pressure of 1.00 atm and a temperature of 25.0°C. What is the pressure of the gas at a volume of 5.00 L and a temperature of 50.0°C?
A. 1.00 atm
B. 2.00 atm
C. 3.00 atm
D. 4.00 atm
Question 6
A 100 mL sample of a salt solution is mixed with 50 mL of 0.1 M HCl. The resulting solution has a pH of 1.5. Calculate the concentration of the salt.
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1.0 M
Question 7
A solution of 0.1 M acetic acid (CH3COOH) is prepared by dissolving 2.5 g of the acid in 100 mL of water. What is the pH of the solution?
A. 2
B. 3
C. 4
D. 5
Question 8
What is the pH of a solution with a hydrogen ion concentration of 1.0 x 10^-3 M?
A. 1
B. 2
C. 3
D. 4
Question 9
A diagram of a titration setup is shown below. If the burette contains 0.1 M NaOH and the initial volume is 10 cm^3, and the final volume is 25 cm^3, calculate the concentration of the acid.
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 10
A solution of silver nitrate is added to a solution of sodium chloride. What is the resulting precipitate?
A. AgCl
B. NaNO3
C. Ag2Cl2
D. NaCl
Question 11
A solution of NaOH is 0.1 M. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 12
A gas occupies a volume of 2.50 L at a pressure of 1.00 atm and a temperature of 25.0°C. What is the volume of the gas at a pressure of 2.00 atm and a temperature of 50.0°C?
A. 3.00 L
B. 4.00 L
C. 5.00 L
D. 6.00 L
Question 13
A solution contains 25.0 mL of 0.100 M HCl and 50.0 mL of 0.0500 M NaOH. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 14
A sample of a metal (M) has a mass of 25.0 g and a volume of 5.00 cm^3. If the density of the metal is 8.00 g/cm^3, what is the molar mass of the metal?
A. 100.0 g/mol
B. 200.0 g/mol
C. 50.0 g/mol
D. 150.0 g/mol
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, ΔHf(C(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol

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