POST UTME RHEMA UNIVERSITY 2020 Chemistry | Objective
Practice these randomly selected questions to test your readiness.
Question 1
Determine the s\tandard Gibbs free energy change for the reaction: 2Ag+(aq) + 2Cl-(aq) → 2AgCl(s) at 298 K and 1 atm. Given: ΔH° = -127.0 kJ/mol, ΔS° = 143 J/mol·K.
Question 2
A 2.0 g sample of a metal (M) is heated in a stream of oxygen gas. The metal is completely oxidized and the mass of the oxide formed is 2.5 g. What is the percentage increase in mass?
Question 3
A 2.5 g sample of a polymer is dissolved in 100 mL of a solvent. The molecular weight of the polymer is 50,000 g/mol. Calculate the number of moles of the polymer.
Question 4
A gas at 300 K has a pressure of 100 kPa. If the temperature is increased to 400 K, what is the new pressure?
Question 5
A 2.5 g sample of a polymer is dissolved in 100 mL of a solvent. The molecular weight of the polymer is 50,000 g/mol. Calculate the number of moles of the polymer.
Question 6
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, what is the initial concentration of HA?
Question 7
Determine the pH of a solution containing 0.1 M HCl and 0.1 M NaOH.
Question 8
The diagram below shows a chemical apparatus setup. Identify the part labeled B.
Question 9
A 2.0 M solution of HCl is titrated with 1.0 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
Question 10
A sample of a hydrocarbon \( C_xH_y \) has a molecular mass of 42 g/mol. The density of the hydrocarbon is 0.8 g/mL. What is the volume of 1.0 g of the hydrocarbon?
Question 11
A 0.500 M solution of NaOH is mixed with 0.500 M solution of HCl. What is the pH of the resulting solution?
Question 12
The reaction between sodium hydroxide and hydrochloric acid is represented by the equation: NaOH + HCl -> NaCl + H2O. If 20 mL of 0.1 M NaOH is added to 20 mL of 0.1 M HCl, calculate the concentration of the resulting solution.
Question 13
The atomic radius of an element is 100 pm. If the element is in its ground state, what is the expected value of its atomic radius in its first excited state?
Question 14
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the resulting solution?
Question 15
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. The initial pH of the solution is 2.0. What is the pH of the solution after the addition of 50 mL of 1.0 M NaOH?
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