POST UTME REDEEMERS UNIVERSITY 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The diagram below shows a chemical apparatus setup.
A. The test tube contains the acid.
B. The burette contains the acid.
C. The test tube contains the base.
D. The burette contains the base.
Question 2
The diagram below shows the structure of a periodic table. Identify the group to which the element with atomic number 16 belongs.
A. Group 1
B. Group 2
C. Group 16
D. Group 18
Question 3
A 2.0 M solution of NaOH is mixed with a 2.0 M solution of HCl. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 4
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M 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 5
An alkane is a type of hydrocarbon that contains only \single bonds between carbon atoms. Which of the following is a correct example of an alkane?
A. Methane
B. Ethane
C. Propane
D. Bu\tane
Question 6
The s\tandard enthalpy of formation (ΔHf°) of H2O(l) is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of H2(g)?
A. 0 kJ/mol
B. 285.8 kJ/mol
C. -285.8 kJ/mol
D. -572.8 kJ/mol
Question 7
A sample of hydrogen gas at 25°C and 1 atm is collected over water at 25°C. What is the partial pressure of the hydrogen gas?
A. 0.5 atm
B. 0.75 atm
C. 1.0 atm
D. 1.25 atm
Question 8
The reaction of sodium with water produces sodium hydroxide and hydrogen gas. Write the balanced chemical equation for this reaction.
A. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
B. Na(s) + H2O(l) → NaOH(aq) + H2(g)
C. 2Na(s) + H2O(l) → 2NaOH(aq)
D. Na(s) + 2H2O(l) → NaOH(aq) + H2(g)
Question 9
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. The resulting solution has a vis\cosity of 0.8 Pa·s. If the density of the polymer is 1.2 g/mL, calculate the number-average molecular weight (Mn) of the polymer.
A. 1000
B. 2000
C. 3000
D. 4000
Question 10
A sample of nitrogen gas occupies a volume of 2.50 L at a pressure of 1.00 atm and a temperature of 298 K. Calculate the number of moles of nitrogen gas present.
A. 0.010 mol
B. 0.020 mol
C. 0.030 mol
D. 0.040 mol
Question 11
The diagram below shows the structure of a molecule. Identify the type of bond between atoms A and B.
A. Sigma (σ) bond
B. Pi (π) bond
C. Sigma (σ) and Pi (π) bond
D. Hydrogen bond
Question 12
A mixture of 1.0 g of sodium chloride (NaCl) and 1.0 g of calcium chloride (CaCl2) is dissolved in 100 mL of water. Calculate the molar concentration of the resulting solution.
A. 0.10 M
B. 0.20 M
C. 0.30 M
D. 0.40 M
Question 13
The s\tandard Gibbs free energy change (ΔG°) for a reaction is related to the s\tandard enthalpy change (ΔH°) and s\tandard entropy change (ΔS°) by the equation: ΔG° = ΔH° - TΔS°. If the s\tandard enthalpy change for a reaction is 50 kJ/mol, the s\tandard entropy change is 0.1 kJ/mol·K, and the temperature is 298 K, what is the s\tandard Gibbs free energy change for the reaction?
A. 4.8 kJ/mol
B. -4.8 kJ/mol
C. 48 kJ/mol
D. -48 kJ/mol
Question 14
A 2.5 M solution of sodium hydroxide is mixed with a 1.0 M solution of hydrochloric acid. What is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 15
Determine the pH of a 0.1 M solution of hydrochloric acid (HCl) at 25°C, given that the dissociation cons\tant of HCl is 10^\( -7 \) and the temperature dep\endence of the dissociation cons\tant is described by the equation: \log(K) = -0.5 \log(T) + 1.5.
A. 1.0
B. 2.0
C. 3.0
D. 4.0

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