POST UTME ESUT 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The half-life of a radioactive subs\tance is 5 years. If a sample of the subs\tance has an initial activity of 100 Bq, what is its activity after 10 years?
A. 50 Bq
B. 25 Bq
C. 12.5 Bq
D. 6.25 Bq
Question 2
A 1.0 M solution of HCl is titrated with 0.5 M NaOH. If 25 mL of HCl is required to reach the equivalence point, what is the number of moles of HCl used?
A. 0.5 mol
B. 1.0 mol
C. 1.5 mol
D. 2.0 mol
Question 3
A 1.00 M solution of $\text{HCl}$ is titrated with 1.00 M $\text{NaOH}$. What is the pH of the solution after 50.0 mL of $\text{NaOH}$ has been added?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 4
Determine the number of moles of $CO_2$ produced when 2.5 g of $CaC_2$ is heated in a stream of $CO_2$ gas at $25^circ C$ and 1 atm.
A. 0.05 mol
B. 0.10 mol
C. 0.15 mol
D. 0.20 mol
Question 5
A sample of a gas at 25°C and 1 atm is compressed to 2 atm at cons\tant temperature. What is the new volume of the gas?
A. 0.5 L
B. 1 L
C. 2 L
D. 4 L
Question 6
A $1.0$ L solution contains $0.50$ mol of $H_2SO_4$. What is the concentration of $H^+$ ions in the solution?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.0 M
Question 7
A solution of 0.1 M NaOH is titrated with 0.1 M HCl. What is the pH of the solution after 25 mL of HCl has been added?
A. 1
B. 2
C. 3
D. 4
Question 8
The reaction between sodium and chlorine is highly exothermic and produces a white solid. The balanced equation is: 2Na(s) + Cl2(g) → 2NaCl(s). What is the type of reaction that occurs in this process?
A. Synthesis reaction
B. Decomposition reaction
C. Combination reaction
D. Displacement reaction
Question 9
The reaction between sulfur trioxide and water is highly exothermic and produces a colorless liquid. The balanced equation is: SO3(g) + H2O(l) → H2SO4(l). What is the type of reaction that occurs in this process?
A. Synthesis reaction
B. Decomposition reaction
C. Combination reaction
D. Neutralization reaction
Question 10
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 11
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. The solution is then diluted to 100 mL. What is the concentration of the polymer solution in g/L?
A. 0.025 g/L
B. 0.05 g/L
C. 0.1 g/L
D. 0.2 g/L
Question 12
Determine the number of moles of CO2 produced when 2.5 g of calcium carbonate (CaCO3) is decomposed completely in a reaction with hydrochloric acid (HCl). The molar mass of CaCO3 is 100.09 g/mol, and the molar mass of CO2 is 44.01 g/mol. The balanced chemical equation for the reaction is: CaCO3 + 2HCl -> CaCl2 + CO2 + H2O.
A. 0.056 mol
B. 0.0565 mol
C. 0.057 mol
D. 0.0575 mol
Question 13
Determine the number of moles of $\text{CO}_2$ produced when 2.50 g of $\text{CaCO}_3$ is decomposed at cons\tant pressure.
A. 0.0250 mol
B. 0.0500 mol
C. 0.100 mol
D. 0.200 mol
Question 14
A 1.0 M solution of HCl is titrated with 0.5 M NaOH. If 25 mL of HCl is required to reach the equivalence point, what is the volume of NaOH required to reach the equivalence point?
A. 12.5 mL
B. 25 mL
C. 50 mL
D. 100 mL
Question 15
A 0.500 g sample of a subs\tance is dissolved in 100.0 mL of solvent. The boiling point elevation of the solution is 0.500°C. What is the molar mass of the subs\tance?
A. 100.0 g/mol
B. 200.0 g/mol
C. 500.0 g/mol
D. 1000.0 g/mol

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