POST UTME SKYLINE UNIVERSITY 2017 Chemistry | Objective

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Question 1
A 2.50 g sample of a metal oxide is heated in a crucible until it decomposes completely. The mass of the metal obtained is 1.25 g. Calculate the percentage of metal in the original sample.
A. 40%
B. 50%
C. 60%
D. 70%
Question 2
A 1.5 g sample of a metal carbonate is heated to produce a metal oxide. Calculate the mass of the metal oxide produced if the metal carbonate has a molar mass of 100 g/mol and the metal oxide has a molar mass of 50 g/mol.
A. 0.75 g
B. 1.0 g
C. 1.25 g
D. 1.5 g
Question 3
The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of zinc in the product ZnSO4?
A. 0
B. +2
C. -2
D. +1
Question 4
The reaction between chlorine gas and potassium iodide is represented by the equation: Cl2 + 2KI → 2KCl + I2. What is the oxidation state of iodine in the product I2?
A. 0
B. -1
C. +1
D. +2
Question 5
A solution of sodium hydroxide is prepared by dissolving 25.0 g of NaOH in 100 mL of water. Calculate the molarity of the solution.
A. 0.500 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 6
A sample of a metal is analyzed and found to have a mass of 20 g. If the metal has a density of 8 g/cm^3, what is the volume of the sample?
A. 2.5 cm^3
B. 5 cm^3
C. 10 cm^3
D. 15 cm^3
Question 7
The reaction between calcium carbonate and hydrochloric acid is represented by the equation: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g). If 2.50 g of CaCO3 is added to 100 mL of 2.00 M HCl, calculate the number of moles of carbon dioxide gas produced.
A. 0.050 mol
B. 0.100 mol
C. 0.150 mol
D. 0.200 mol
Question 8
A 25.0 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 25.0 mL of NaOH?
A. 2
B. 3
C. 4
D. 5
Question 9
A 2.0 M solution of sodium hydroxide (NaOH) is prepared by dissolving 40 g of NaOH in water to make 1.0 L of solution. What is the molarity of the solution?
A. 1.0 M
B. 2.0 M
C. 3.0 M
D. 4.0 M
Question 10
A solution of sodium chloride is prepared by dissolving 25.0 g of NaCl in 100 mL of water. Calculate the molarity of the solution.
A. 0.500 M
B. 1.00 M
C. 2.00 M
D. 3.00 M
Question 11
A 25.0 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 20.0 mL of NaOH?
A. 2
B. 3
C. 4
D. 5
Question 12
A sample of gas occupies a volume of 2.5 liters at a pressure of 1.5 atm. What is the volume of the gas at a pressure of 3.0 atm, assuming the temperature remains cons\tant?
A. 1.0 L
B. 1.5 L
C. 2.0 L
D. 2.5 L
Question 13
The reaction between nitrogen dioxide and water is given by the equation: 3NO2 + H2O → 2HNO3 + NO. If 2.5 moles of NO2 react with excess water, what is the limiting reac\tant?
A. NO2
B. H2O
C. HNO3
D. NO
Question 14
A 25 mL sample of a 0.1 M solution of H2SO4 is titrated with 0.1 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 15
A solution of 0.1 M NaCl is electrolyzed u\sing a platinum electrode. If the cell potential is 2.71 V, calculate the current flowing through the cell.
A. 0.1 A
B. 0.2 A
C. 0.3 A
D. 0.4 A

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