POST UTME SUMMIT UNIVERSITY 2023 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 the initial amount of the subs\tance is 100g, how much of the subs\tance will remain after 15 years?
A. 12.5g
B. 25g
C. 50g
D. 100g
Question 2
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol, ΔHf(C(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 3
A solution of 0.1M HCl is titrated with 0.1M NaOH. If 20ml of NaOH is required to reach the equivalence point, what is the concentration of HCl?
A. 0.1M
B. 0.2M
C. 0.3M
D. 0.4M
Question 4
The molar mass of a compound is 180 g/mol. If 2.5 g of the compound is dissolved in 50 mL of water, what is the concentration of the solution in g/L?
A. 0.1 g/L
B. 0.2 g/L
C. 0.5 g/L
D. 1.0 g/L
Question 5
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. The s\tandard enthalpy of formation of H2O is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of CH4?
A. -74.8 kJ/mol
B. -74.9 kJ/mol
C. -75.0 kJ/mol
D. -75.1 kJ/mol
Question 6
A 2.5 M solution of sodium hydroxide (NaOH) is prepared by dissolving 2.5 g of NaOH in water to make 250 mL of solution. What is the concentration of the solution in terms of molarity?
A. 0.01 M
B. 0.1 M
C. 1 M
D. 10 M
Question 7
A 2.00 g sample of a non-metallic oxide of nitrogen is dissolved in 25.0 cm³ of water. The solution is then titrated with 0.100 M HCl. If 25.0 cm³ of 0.100 M HCl is required to reach the equivalence point, calculate the molar mass of the oxide.
A. 62.0 g/mol
B. 62.5 g/mol
C. 63.0 g/mol
D. 64.0 g/mol
Question 8
A 2.5 M solution of HCl is titrated with 0.5 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 9
A metal M has a s\tandard electrode potential (E°) of -0.5 V. What is the s\tandard Gibbs free energy change (ΔG°) for the reaction: M → M^+ + e^-?
A. 0.5 kJ/mol
B. 1.0 kJ/mol
C. 1.5 kJ/mol
D. 2.0 kJ/mol
Question 10
The rate cons\tant for a first-order reaction is 0.05 min^-1. If the initial concentration of the reac\tant is 0.1 M, what is the concentration of the reac\tant after 10 minutes?
A. 0.005 M
B. 0.01 M
C. 0.05 M
D. 0.1 M
Question 11
A solution of 0.1M HCl is titrated with 0.1M NaOH. If 20ml of NaOH is required to reach the equivalence point, what is the volume of HCl required to reach the equivalence point?
A. 20ml
B. 40ml
C. 60ml
D. 80ml
Question 12
The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). What is the oxidation state of copper in the product Cu(s)?
A. 0
B. +1
C. +2
D. -1
Question 13
A metal M has a s\tandard electrode potential (E°) of +1.0 V. What is the s\tandard Gibbs free energy change (ΔG°) for the reaction: M → M^+ + e^-?
A. 1.0 kJ/mol
B. 2.0 kJ/mol
C. 3.0 kJ/mol
D. 4.0 kJ/mol
Question 14
A metal M has a s\tandard electrode potential (E°) of +0.5 V. What is the s\tandard Gibbs free energy change (ΔG°) for the reaction: M → M^+ + e^-?
A. -0.5 kJ/mol
B. -1.0 kJ/mol
C. -1.5 kJ/mol
D. -2.0 kJ/mol
Question 15
A gas at 25°C and 1 atm is compressed to 2 atm at cons\tant temperature. What is the final volume of the gas?
A. 1 L
B. 2 L
C. 3 L
D. 4 L

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