POST UTME AL-HIKMAH UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The reaction between sodium and chlorine produces a white solid. If 2.50 g of sodium reacts with 1.50 g of chlorine, what is the limiting reac\tant?
A. sodium
B. chlorine
C. neither
D. both
Question 2
A 2.00 M solution of sodium hydroxide (NaOH) is titrated with a 1.00 M solution of hydrochloric acid (HCl). If 25.0 mL of the HCl solution is required to reach the equivalence point, what is the volume of the NaOH solution required to reach the equivalence point?
A. 50.0 mL
B. 75.0 mL
C. 100.0 mL
D. 125.0 mL
Question 3
A diagram of a chemical apparatus is shown below. Identify the purpose of the apparatus.
A. To measure the volume of a liquid
B. To measure the mass of a solid
C. To measure the temperature of a solution
D. To measure the pH of a solution
Question 4
A mixture of 2.00 g of an unknown gas and 3.00 g of oxygen is heated to 100°C at 1.00 atm. If the total pressure is 2.00 atm, what is the partial pressure of the unknown gas?
A. 0.50 atm
B. 1.00 atm
C. 1.50 atm
D. 2.00 atm
Question 5
A 1.0 M solution of FeCl3 is electrolyzed at a cons\tant current of 2.0 A for 10 minutes. What is the mass of Cl2 gas collected?
A. 0.5 g
B. 1.0 g
C. 1.5 g
D. 2.0 g
Question 6
A 25.0 g sample of a metal (M) is heated in a crucible until it melts. The mass of the crucible and the metal is 25.5 g. The mass of the crucible alone is 10.0 g. What is the molar mass of the metal (M)?
A. 50.0 g/mol
B. 60.0 g/mol
C. 70.0 g/mol
D. 80.0 g/mol
Question 7
Determine the solubility of silver chloride (AgCl) in water at 25°C, given that the solubility product cons\tant (Ksp) is 1.8 × 10^-10. The molar solubility of AgCl is denoted by 's'.
A. 1.0 × 10^-5 M
B. 1.0 × 10^-6 M
C. 1.0 × 10^-7 M
D. 1.0 × 10^-8 M
Question 8
A diagram of the periodic table is shown below. Identify the group number of the element with atomic number 12.
A. 1
B. 2
C. 3
D. 4
Question 9
A solution of 1.00 M sodium chloride is mixed with a solution of 2.00 M calcium chloride. What is the resulting concentration of calcium ions?
A. 0.50 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 10
The half-life of a radioactive subs\tance is 5 days. If 100 mg of the subs\tance is present initially, how much will remain after 15 days?
A. 12.5 mg
B. 25 mg
C. 50 mg
D. 100 mg
Question 11
A 25% solution of glu\cose in water is to be diluted to 10% solution by adding 250 mL of water. Calculate the initial volume of the glu\cose solution.
A. 100 mL
B. 200 mL
C. 300 mL
D. 400 mL
Question 12
A 1.0 M solution of KNO3 is electrolyzed at a cons\tant current of 1.0 A for 5 minutes. What is the mass of O2 gas collected?
A. 0.5 g
B. 1.0 g
C. 1.5 g
D. 2.0 g
Question 13
A sample of 1.00 g of an unknown hydrocarbon is burned in a combustion reaction. If 1.50 g of carbon dioxide is produced, what is the empirical formula of the hydrocarbon?
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 14
A 2.5 M solution of H2SO4 is titrated with 0.5 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. 1.5
B. 2.5
C. 3.5
D. 4.5
Question 15
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. What is the pH of the solution after 20 mL of HCl has been added?
A. 7.0
B. 8.0
C. 9.0
D. 10.0

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