POST UTME DELSU 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.5 M solution of sodium hydroxide (NaOH) is titrated with a 2.5 M solution of hydrochloric acid (HCl). Calculate the pH of the solution after 25 mL of HCl has been added.
A. 7
B. 8
C. 9
D. 10
Question 2
Determine the rate cons\tant (k) for the first-order reaction: A → B, given that the initial concentration of A is 0.1 M and the concentration of A after 2 minutes is 0.05 M.
A. \( k = \frac{2.303}{t} \log \frac{[A]_0}{[A]_t} \)
B. \( k = \frac{[A]_t}{[A]_0} \)
C. \( k = \frac{t}{[A]_0} \)
D. \( k = \frac{2.303}{t} \log \frac{[A]_t}{[A]_0} \)
Question 3
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of methane (CH4(g)) at 298 K.
A. -890 kJ/mol
B. -890.5 kJ/mol
C. -891 kJ/mol
D. -891.5 kJ/mol
Question 4
A 2.5 M solution of sodium hydroxide (NaOH) is titrated with a 2.5 M solution of hydrochloric acid (HCl). Calculate the volume of HCl required to neutralize 25 mL of NaOH.
A. 12.5 mL
B. 25 mL
C. 37.5 mL
D. 50 mL
Question 5
A 0.1 M solution of NaOH is prepared by dissolving 4 g of NaOH in 100 mL of water. What is the concentration of the solution in g/L?
A. 0.4 g/L
B. 0.8 g/L
C. 1.2 g/L
D. 1.6 g/L
Question 6
The atomic radius of an element is 100 pm. If the element is in its ground state, what is the expected value of its atomic radius in the excited state?
A. 110 pm
B. 90 pm
C. 120 pm
D. 130 pm
Question 7
A 25 mL sample of 0.5 M HCl is titrated with 0.5 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 10 mL
B. 20 mL
C. 25 mL
D. 30 mL
Question 8
A 0.1 M solution of HCl is prepared by dissolving 2 g of HCl in 100 mL of water. What is the concentration of the solution in g/L?
A. 0.2 g/L
B. 0.4 g/L
C. 0.6 g/L
D. 0.8 g/L
Question 9
A metal has a s\tandard enthalpy of formation of -200 kJ/mol. What is the s\tandard enthalpy of combustion of the metal?
A. -100 kJ/mol
B. -150 kJ/mol
C. -200 kJ/mol
D. -250 kJ/mol
Question 10
A solution containing 10 g of glu\cose (C6H12O6) is prepared by dissolving the glu\cose in 100 mL of water. What is the concentration of the solution in g/L?
A. 10 g/L
B. 20 g/L
C. 30 g/L
D. 40 g/L
Question 11
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is present initially, how much will remain after 10 years?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g
Question 12
A 2.5 M solution of hydrochloric acid (HCl) is titrated with a 2.5 M solution of sodium hydroxide (NaOH). Calculate the volume of NaOH required to neutralize 25 mL of HCl.
A. 12.5 mL
B. 25 mL
C. 37.5 mL
D. 50 mL
Question 13
A gas has a volume of 2.5 L at a pressure of 1.5 atm. What is the volume of the gas at a pressure of 3.0 atm?
A. 1.5 L
B. 2.0 L
C. 2.5 L
D. 3.0 L
Question 14
Determine the number of moles of electrons transferred in the reaction: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s). Given that 2.5 g of Zn is used and the reaction occurs at 25°C.
A. 1 mole
B. 2 moles
C. 3 moles
D. 4 moles
Question 15
A metal oxide has the formula MO2. If the metal has an oxidation state of +2, what is the charge on the oxide ion?
A. -2
B. +2
C. -4
D. +4

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