POST UTME JOSEPH AYO BABALOLA UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy of formation of water (H2O) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of hydrogen gas (H2) to form H2O.
A. -285.8
B. -286.8
C. -287.8
D. -288.8
Question 2
A solution contains 25 g of glu\cose (C6H12O6) dissolved in 100 mL of water. What is the molarity of the solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M
Question 3
The diagram below shows a titration curve for the reaction between HCl and NaOH.
A. The reaction is exothermic.
B. The reaction is \endothermic.
C. The reaction is neutral.
D. The reaction is acidic.
Question 4
A solution contains 0.100 M CaCl2 and 0.0500 M Na2SO4. What is the concentration of Ca2+ ions in the solution?
A. 0.0250 M
B. 0.0500 M
C. 0.100 M
D. 0.200 M
Question 5
A 2.00 M solution of HCl is titrated with 0.500 M NaOH. If 30.0 mL of NaOH is required to reach the equivalence point, what is the volume of HCl in liters?
A. 60.0 mL
B. 75.0 mL
C. 90.0 mL
D. 120 mL
Question 6
The reaction of nitrogen dioxide with water is highly exothermic. Write the balanced chemical equation for this reaction, including the s\tandard enthalpy change (ΔH°) in kJ/mol.
A. \text{N}_2\text{O}_2 + \text{H}_2\text{O} \rightarrow \text{HNO}_3 + \text{NO}
B. \text{N}_2\text{O}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{NO}_3 + \text{NO}
C. \text{N}_2\text{O}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{O}_2 + \text{NO}_2
D. \text{N}_2\text{O}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{O}_2 + \text{NO}_2
Question 7
A 2.00 M solution of HCl is titrated with 1.00 M NaOH. If 25.0 mL of NaOH is required to reach the equivalence point, what is the concentration of HCl?
A. 0.500 M
B. 1.00 M
C. 2.00 M
D. 4.00 M
Question 8
A sample of gas occupies a volume of 5.0 L at a pressure of 2.0 atm. What is the pressure of the gas if the volume is increased to 10.0 L?
A. 1.0 atm
B. 1.5 atm
C. 2.0 atm
D. 2.5 atm
Question 9
The half-life of a radioactive subs\tance is 5.00 days. If 100.0 mg of the subs\tance is initially present, what is the amount remaining after 20.0 days?
A. 10.0 mg
B. 20.0 mg
C. 30.0 mg
D. 40.0 mg
Question 10
The ideal gas law is given by PV = nRT. What is the unit of the gas cons\tant R?
A. J/mol·K
B. Pa·m³/mol·K
C. kg/mol·K
D. m³/mol·K
Question 11
A polymer is a large molecule composed of many repeated subunits called monomers. Which of the following is a characteristic of a polymer?
A. It has a high melting point
B. It has a low boiling point
C. It is soluble in water
D. It has a high molecular weight
Question 12
A sample of gas occupies a volume of 2.5 L at a pressure of 1.5 atm. What is the pressure of the gas if the volume is reduced to 1.2 L?
A. 2.1 atm
B. 2.5 atm
C. 3.0 atm
D. 3.5 atm
Question 13
The diagram below shows a titration setup. Identify the subs\tance being titrated.
A. HCl
B. NaOH
C. H_2SO_4
D. Na_2CO_3
Question 14
The atomic number of an element is 20. What is the number of protons in the nucleus of an atom of this element?
A. 18
B. 20
C. 22
D. 24
Question 15
A solution contains 30 g of sodium chloride (NaCl) dissolved in 100 mL of water. What is the molarity of the solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M

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