POST UTME AAUA 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Determine the oxidation state of the underlined atom in the compound H2SO4.
A. +6
B. +4
C. +2
D. +1
Question 2
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the solution
B. To measure the concentration of the solution
C. To mix the solutions
D. To separate the solutions
Question 3
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 4
Determine the number of moles of electrons transferred during the electrolysis of 2.5 L of water at 25°C, given that the cell potential is 1.23 V and the current is 0.5 A.
A. 0.5 mol
B. 1.0 mol
C. 1.5 mol
D. 2.0 mol
Question 5
A 2.00 M solution of a weak acid HA is 5.00% dissociated. What is the pH of the solution?
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 6
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, and ΔHf(Ca(s)) = -178.2 kJ/mol.
A. -1206.7 kJ/mol
B. -1206.8 kJ/mol
C. -1206.9 kJ/mol
D. -1206.6 kJ/mol
Question 7
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after 15.0 mL of NaOH has been added.
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 8
A 2.5 L flask contains 0.5 mol of an ideal gas at 27°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 1.01 x 10^5 Pa
B. 2.02 x 10^5 Pa
C. 3.03 x 10^5 Pa
D. 4.04 x 10^5 Pa
Question 9
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 10
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 11
The diagram below shows a setup for electrolysis. Identify the product formed at the cathode.
A. H2
B. O2
C. Na
D. Cl2
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
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 14
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
Question 15
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

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