POST UTME BELLS UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of polystyrene has a molecular weight of 100,000 g/mol. What is the number of monomer units in the polymer chain?
A. 100
B. 1000
C. 10,000
D. 100,000
Question 2
A 1 M solution of H2SO4 is titrated with 1 M NaOH. If 50 mL of the acid is required to reach the equivalence point, what is the concentration of the acid?
A. 0.5 M
B. 1 M
C. 2 M
D. 4 M
Question 3
A 5.00-mL sample of a solution containing 0.100 M NaOH is mixed with 10.0 mL of a solution containing 0.0500 M HCl. What is the concentration of OH- ions in the resulting solution?
A. 0.0250 M
B. 0.0500 M
C. 0.0750 M
D. 0.100 M
Question 4
A solution contains 0.2 g of KCl per 100 mL. What is the concentration of the solution in g/L?
A. 0.2 g/L
B. 0.5 g/L
C. 1 g/L
D. 2 g/L
Question 5
The following diagram shows a titration setup for the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH). Identify the subs\tance being titrated.
A. HCl (aq)
B. NaOH (aq)
C. NaCl (aq)
D. H2O (l)
Question 6
A diagram of a electrolysis cell is shown below. Identify the product formed at the cathode.
A. H2
B. O2
C. Na
D. Cl2
Question 7
A 10.0 g sample of a mixture containing 80.0% sodium chloride (NaCl) and 20.0% water (H2O) is heated to produce sodium hydroxide (NaOH) and hydrogen chloride (HCl). Calculate the mass of NaOH produced.
A. 2.50 g
B. 5.00 g
C. 7.50 g
D. 10.0 g
Question 8
A 25.0 mL sample of a solution containing 0.100 M sodium hydroxide (NaOH) is titrated with 0.0500 M hydrochloric acid (HCl). Calculate the volume of HCl required to reach the equivalence point.
A. 12.5 mL
B. 25.0 mL
C. 37.5 mL
D. 50.0 mL
Question 9
The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is a classic example of a neutralization reaction. Write the balanced chemical equation for this reaction, including the state of each subs\tance.
A. HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l)
B. HCl (aq) + NaOH (aq) → NaCl (s) + H2O (l)
C. HCl (g) + NaOH (aq) → NaCl (aq) + H2O (l)
D. HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (g)
Question 10
A 25 mL sample of a 0.5 M solution of sodium carbonate (Na2CO3) is titrated with a 1 M solution of hydrochloric acid (HCl). Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.0125 mol
B. 0.025 mol
C. 0.0375 mol
D. 0.05 mol
Question 11
A 1 M solution of HNO3 is titrated with 1 M NaOH. If 50 mL of the acid is required to reach the equivalence point, what is the concentration of the acid?
A. 0.5 M
B. 1 M
C. 2 M
D. 4 M
Question 12
A solution contains 0.5 g of NaCl per 100 mL. What is the concentration of the solution in g/L?
A. 0.5 g/L
B. 1 g/L
C. 2 g/L
D. 5 g/L
Question 13
A solution contains 0.1 g of Na2SO4 per 100 mL. What is the concentration of the solution in g/L?
A. 0.1 g/L
B. 0.5 g/L
C. 1 g/L
D. 2 g/L
Question 14
The rate cons\tant (k) for a first-order reaction is given by the equation: k = 2.303/t \log10\( A0/A \). If the initial concentration (A0) is 0.1 M and the concentration after 10 minutes (A) is 0.05 M, what is the value of k?
A. 0.0005 min^-1
B. 0.001 min^-1
C. 0.005 min^-1
D. 0.01 min^-1
Question 15
A 2.50-g sample of a compound containing only carbon and hydrogen is found to have a mass of 2.00 g when heated in a stream of oxygen gas. The mass of the carbon dioxide produced is 3.75 g. Calculate the empirical formula of the compound.
A. CH2
B. C2H4
C. C3H6
D. C4H8

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