POST UTME GREENFIELD UNIVERSITY 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal rod of length 20.0 cm and radius 1.0 cm is heated to a temperature of 100°C. Calculate the energy required to raise the temperature of the rod to 200°C.
A. 1600
B. 3200
C. 4800
D. 6400
Question 2
What is the molar mass of a compound composed of 40% carbon and 60% oxygen by mass?
A. 60 g/mol
B. 80 g/mol
C. 100 g/mol
D. 120 g/mol
Question 3
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. What is the pH of the resulting solution?
A. 7
B. 8
C. 9
D. 10
Question 4
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. What is the s\tandard enthalpy of formation of H2O(g) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol?
A. -241.8 kJ/mol
B. -285.8 kJ/mol
C. -393.5 kJ/mol
D. -572.8 kJ/mol
Question 5
The half-life of a radioactive subs\tance is 5.00 years. If 100 g of the subs\tance is initially present, how much of the subs\tance will remain after 10.0 years?
A. 50.0 g
B. 25.0 g
C. 12.5 g
D. 6.25 g
Question 6
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 7
A 0.5 M solution of NaOH is titrated with 0.1 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. ( 50 ) mL
B. ( 100 ) mL
C. ( 150 ) mL
D. ( 200 ) mL
Question 8
A 25 mL sample of 0.5 M H2SO4 is titrated with 1 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 9
A 2.00 M solution of HCl is mixed with a 2.00 M solution of NaOH. What is the resulting pH?
A. 0.00
B. 1.00
C. 2.00
D. 3.00
Question 10
A 2.0 M solution of hydrochloric acid (HCl) is prepared by dissolving 40.0 g of HCl in 1.0 L of water. Calculate the concentration of HCl in the solution.
A. 1.1
B. 1.2
C. 1.3
D. 1.4
Question 11
Determine the pH of a 0.1 M solution of acetic acid (CH3COOH) at 25°C.
A. 3.5
B. 4.5
C. 5.5
D. 6.5
Question 12
The reaction between hydrogen gas (H2) and oxygen gas (O2) is highly exothermic. Write a balanced chemical equation for the reaction, including the s\tandard enthalpy change (ΔH°) for the reaction.
A. 2H2 + O2 → 2H2O, \u0394H° = -572 kJ/mol
B. H2 + O2 → H2O, \u0394H° = -286 kJ/mol
C. 2H2 + O2 → 2H2O, \u0394H° = -286 kJ/mol
D. H2 + O2 → H2O, \u0394H° = -572 kJ/mol
Question 13
A 0.5 M solution of calcium chloride (CaCl2) is prepared by dissolving 0.25 mol of CaCl2 in 0.5 L of water. What is the concentration of calcium ions \( Ca2+ \) in the solution?
A. 0.25 M
B. 0.5 M
C. 1.0 M
D. 1.5 M
Question 14
A 2.5 g sample of a metal carbonate is treated with 20 cm³ of 0.5 M HCl. If 10 cm³ of the excess acid is titrated with 0.1 M NaOH, calculate the molar mass of the metal.
A. 50
B. 75
C. 100
D. 125
Question 15
The reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl) is highly exothermic. Calculate the s\tandard enthalpy change (ΔH°) for the reaction, given that the s\tandard enthalpy of formation (ΔH°f) for NaOH is -469.8 kJ/mol and for HCl is -92.3 kJ/mol.
A. NaOH + HCl → NaCl + H2O
B. -377.5 kJ/mol
C. NaOH + HCl → NaCl + H2O + heat
D. The reaction is \endothermic

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