POST UTME AAUA 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.5 g sample of a non-metallic oxide of nitrogen is decomposed by heating with graphite in a stream of hydrogen. The volume of hydrogen gas produced at 25°C and 1 atm is 2.5 L. Calculate the percentage yield of the reaction.
A. 50%
B. 60%
C. 70%
D. 80%
Question 2
Determine the oxidation state of the underlined metal atom in the compound [Cr(H2O)6]Cl3.
A. +3
B. +2
C. +1
D. +6
Question 3
A 10% solution of a non-metallic oxide of nitrogen in water has a density of 1.2 g/mL. Calculate the molarity of the solution.
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M
Question 4
A solution contains 0.0500 M NH3 and 0.0500 M NH4Cl. What is the pH of the solution?
A. 9.25
B. 9.50
C. 9.75
D. 10.00
Question 5
A 0.1 M solution of HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, calculate the volume of HCl required to reach the equivalence point.
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 6
The diagram below shows a molecular structure. What is the type of bond between the two atoms?
A. Covalent
B. Ionic
C. Hydrogen
D. Polar Covalent
Question 7
A 2.50 g sample of a non-metallic element (X) is heated in a crucible to produce 1.25 g of X2O5. What is the empirical formula of the element?
A. O2S
B. SO2
C. SO3
D. SO4
Question 8
A 0.1 M solution of HCl is mixed with a 0.1 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 7
C. 10
D. 14
Question 9
A 50.0 mL sample of a 0.500 M solution of H2SO4 is mixed with 50.0 mL of a 0.500 M solution of NaOH. What is the resulting pH?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 10
A 5.00 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 2.50 L at 25°C and 1.00 atm. What is the empirical formula of the compound?
A. CH4
B. C2H4
C. C3H6
D. C4H8
Question 11
A 2.00 M solution of sodium nitrate (NaNO3) is mixed with 1.00 M solution of barium chloride (BaCl2). What is the resulting concentration of the solution?
A. 1.00 M
B. 1.50 M
C. 2.00 M
D. 3.00 M
Question 12
A solution of a non-metallic oxide of nitrogen in water has a pH of 9.5. Calculate the concentration of the oxide in moles per liter.
A. 0.01 M
B. 0.05 M
C. 0.1 M
D. 0.2 M
Question 13
The diagram below shows the structure of a hydrocarbon. What is the name of the compound?
A. Cyclohexane
B. Cyclohexene
C. Benzene
D. Toluene
Question 14
The diagram below shows a setup for electrolysis. Identify the product formed at the cathode.
A. H2
B. O2
C. Na
D. Cl2
Question 15
A 2.5 g sample of a non-metallic oxide of nitrogen is decomposed by heating with graphite in a stream of hydrogen. The volume of hydrogen gas produced at 25°C and 1 atm is 2.5 L. Calculate the molar mass of the oxide.
A. 60 g/mol
B. 80 g/mol
C. 100 g/mol
D. 120 g/mol

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