POST UTME MOUNTAIN TOP UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.5 g sample of a non-metallic element is heated in a crucible until it reaches a temperature of 2500°C. If the mass of the crucible and the element is 10 g, what is the percentage increase in mass?
A. 10%
B. 20%
C. 30%
D. 40%
Question 2
The half-life of a radioactive subs\tance is 5.27 years. If the initial amount of the subs\tance is 100 g, what is the amount remaining after 10.54 years?
A. 50 g
B. 50 g
C. 50 g
D. 50 g
Question 3
Determine the bond order of the molecule O2 u\sing the molecular orbital diagram. Assume that the energy levels are given by the equation \( E_n = -\frac{13.6}{n^2} , \text{eV} \).
A. 1
B. 2
C. 3
D. 4
Question 4
A gas at 25°C and 1 atm has a volume of 2.5 L. What is the volume of the gas at 50°C and 2 atm?
A. 5 L
B. 6 L
C. 7 L
D. 8 L
Question 5
A metal M reacts with oxygen to form a compound MO. The molar mass of M is 55.85 g/mol and that of MO is 79.87 g/mol. What is the percentage composition of M in MO?
A. 69.5%
B. 69.5%
C. 69.5%
D. 69.5%
Question 6
A solution of sodium hydroxide is titrated with a solution of hydrochloric acid. If 25 mL of the acid solution is required to neutralize 15 mL of the base solution, what is the concentration of the acid solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 7
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the metal oxide has a molar mass of 120 g/mol and the gas evolved has a volume of 2.5 L at 25°C and 1 atm, what is the molar mass of the metal carbonate?
A. 150 g/mol
B. 180 g/mol
C. 200 g/mol
D. 220 g/mol
Question 8
The diagram below shows a titration setup for the determination of the concentration of a weak acid.
A. The burette contains the acid.
B. The beaker contains the acid.
C. The burette contains the base.
D. The beaker contains the base.
Question 9
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution at the equivalence point?
A. 7
B. 10
C. 14
D. 12
Question 10
A 2.0 g sample of a non-metallic element is heated in a crucible until it reaches a temperature of 2500°C. If the mass of the crucible and the element is 10 g, what is the percentage increase in mass?
A. 10%
B. 20%
C. 30%
D. 40%
Question 11
A 1.0 M solution of NaOH is titrated with 1.0 M HCl. If 20 mL of HCl is added, 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 12
The electrolysis of a solution of copper(II) sulfate u\sing a copper electrode results in the formation of copper metal and oxygen gas. Write the half-equation for the reduction of copper(II) ions at the copper electrode.
A. Cu2+ + 2e- → Cu
B. Cu2+ + e- → Cu+
C. Cu2+ + 2e- → 2Cu
D. Cu2+ + e- → Cu
Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) if the s\tandard enthalpy of formation of CaO(s) is -635.09 kJ/mol and that of CO2(g) is -393.5 kJ/mol.
A. -1782.59 kJ/mol
B. -1782.59 kJ/mol
C. -1782.59 kJ/mol
D. -1782.59 kJ/mol
Question 14
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is added, what is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 15
A 2.0 M solution of H2SO4 is mixed with a 2.0 M solution of NaOH. What is the resulting concentration of the solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M

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