POST UTME COAL CITY UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The reaction of magnesium metal with hydrochloric acid produces magnesium chloride and hydrogen gas. Write the balanced chemical equation for this reaction.
A. \text{Mg}(s) + \text{HCl}(aq) \rightarrow \text{MgCl}(aq) + \text{H}_2(g)
B. \text{Mg}(s) + 2\text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g)
C. \text{Mg}(s) + \text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g)
D. \text{Mg}(s) + \text{H}_2\text{O}(l) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g)
Question 2
A 2.5 g sample of a compound containing only carbon and hydrogen is burned in a combustion apparatus. The volume of carbon dioxide produced at STP is 2.5 L. What is the empirical formula of the compound?
A. CH4
B. C2H6
C. C3H8
D. C4H10
Question 3
A solution of sodium hydroxide (NaOH) is titrated with a solution of hydrochloric acid (HCl). If 25.0 mL of 0.100 M NaOH is required to neutralize 20.0 mL of HCl, calculate the concentration of the HCl solution.
A. 0.050 M
B. 0.100 M
C. 0.200 M
D. 0.500 M
Question 4
The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of zinc in this reaction?
A. 0
B. +2
C. -2
D. +1
Question 5
A sample of nitrogen gas (N2) is collected over water at a temperature of 298 K and a pressure of 1 atm. If the vapor pressure of water at this temperature is 0.0313 atm, calculate the partial pressure of N2 in the sample.
A. 0.9687 atm
B. 0.0313 atm
C. 1 atm
D. 0.9687 atm
Question 6
A catalyst is added to a reaction mixture. Which of the following statements is true?
A. The reaction rate increases.
B. The reaction rate decreases.
C. The reaction equilibrium shifts to the left.
D. The reaction equilibrium shifts to the right.
Question 7
A solution of 1.0 M HCl is mixed with a solution of 1.0 M NaOH. What is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 8
A 1.0 M solution of HCl is mixed with a 1.0 M solution of NaOH. If 50 mL of each solution is used, what is the concentration of the resulting solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M
Question 9
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. The solution is then titrated with a 0.1 M solution of a strong acid. The equivalence point is reached when 25 mL of the acid has been added. What is the molar mass of the polymer?
A. 5000\text{ g/mol}
B. 6000\text{ g/mol}
C. 7000\text{ g/mol}
D. 8000\text{ g/mol}
Question 10
The s\tandard enthalpy of formation of carbon dioxide is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of carbon monoxide?
A. -283.5\text{ kJ/mol}
B. -393.5\text{ kJ/mol}
C. -493.5\text{ kJ/mol}
D. -593.5\text{ kJ/mol}
Question 11
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To measure the pH of the solution
Question 12
A 2.5 L flask contains 0.25 mol of an ideal gas at 25°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 1.01 x 10^5 Pa
B. 2.46 x 10^5 Pa
C. 3.01 x 10^5 Pa
D. 4.01 x 10^5 Pa
Question 13
The diagram below shows a chemical apparatus setup.
A. The solution in beaker A is a strong acid.
B. The solution in beaker A is a weak acid.
C. The solution in beaker A is a strong base.
D. The solution in beaker A is a weak base.
Question 14
The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100 g, what is the amount remaining after 10 years?
A. 50
B. 25
C. 12.5
D. 6.25
Question 15
The element with atomic number 16 is placed in group 16 of the periodic table. What is the expected oxidation state of this element in its compounds?
A. 0
B. -2
C. +2
D. +4

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