POST UTME ELIZADE UNIVERSITY 2018 Chemistry | Objective
Practice these randomly selected questions to test your readiness.
Question 1
The diagram below shows a setup for electrolysis of a solution of an acid. Identify the product formed at the cathode.
Question 2
A 5.0 M solution of HCl is mixed with a 2.0 M solution of NaOH. What is the resulting concentration of the solution after the reaction is complete?
Question 3
The rate cons\tant for the decomposition of N2O5 is 2.50 × 10^\( -3 \) s^\( -1 \) at 298 K. What is the half-life of the reaction?
Question 4
The reaction of ethanol with sulfuric acid is as follows: C2H5OH + H2SO4 → C2H5OSO3H + H2O. If 1.00 mol of ethanol reacts with 1.00 mol of sulfuric acid, what is the product formed?
Question 5
A solution of sodium hydroxide is titrated with a solution of hydrochloric acid. The initial pH of the sodium hydroxide solution is 12.0. After the addition of 20.0 mL of hydrochloric acid, the pH of the solution is 10.0. What is the concentration of the hydrochloric acid solution?
Question 6
A solution of sulfuric acid \( H_2SO_4 \) is prepared by dissolving 50.0 g of H_2SO_4 in 100 mL of water. What is the molarity of the solution?
Question 7
A metal M reacts with HCl to form a salt and H2 gas. The reaction is as follows: M + 2HCl → MCl2 + H2. If 2.50 g of M reacts with 2.50 g of HCl, what is the mass of MCl2 formed?
Question 8
A 3.0 g sample of a polymer is dissolved in 200 mL of a solvent. The solution is then titrated with a solution of a strong acid. The initial pH of the solution is 7.0. After the addition of 15.0 mL of the acid solution, the pH of the solution is 4.5. What is the molecular weight of the polymer?
Question 9
A solution of sodium chloride (NaCl) is prepared by dissolving 35.5 g of NaCl in 100 mL of water. What is the molar concentration of the solution?
Question 10
Determine the s\tandard Gibbs free energy change (ΔG°) for the reaction: 2Ag+(aq) + 2Cl-(aq) → 2AgCl(s) at 298 K, given that the s\tandard enthalpy change (ΔH°) is -127.5 kJ/mol and the s\tandard entropy change (ΔS°) is -173.5 J/mol·K.
Question 11
At 273 K, 1.00 L of an ideal gas at 1.00 atm occupies a volume of 22.4 L. What is the volume of 0.500 mol of the gas at 273 K and 1.00 atm?
Question 12
A 2.0 g sample of a polymer is dissolved in 100 mL of a solvent. The solution is then titrated with a solution of a strong acid. The initial pH of the solution is 7.0. After the addition of 10.0 mL of the acid solution, the pH of the solution is 4.0. What is the molecular weight of the polymer?
Question 13
The diagram below shows a setup for a titration experiment. Identify the subs\tance being titrated.
Question 14
A solution of sodium hydroxide is titrated with a solution of hydrochloric acid. The initial pH of the sodium hydroxide solution is 12.0. After the addition of 25.0 mL of hydrochloric acid, the pH of the solution is 10.5. What is the concentration of the hydrochloric acid solution?
Question 15
A 2.0 g sample of a non-metallic oxide of nitrogen is heated in a stream of hydrogen gas. The resulting gas is passed through a solution of sodium hydroxide, and the volume of the gas collected is 3.0 liters at 25°C and 1 atm. What is the empirical formula of the oxide?
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