POST UTME RHEMA UNIVERSITY 2021 Chemistry | Objective

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Question 1
The diagram below shows a titration setup. What is the purpose of the burette?
A. To measure the volume of the titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To measure the pH of the solution
Question 2
A 10.0 mL sample of 0.100 M H2SO4 is added to a 20.0 mL sample of 0.0500 M NaOH. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 3
A 10 mL sample of a solution containing 0.1 M NaOH is titrated with 0.1 M HCl. What is the pH of the solution after the titration?
A. 7.0
B. 8.0
C. 9.0
D. 10.0
Question 4
A polymer has a molecular weight of 50000 g/mol and a degree of polymerization of 200. Calculate the molar mass of the repeating unit.
A. \( 250 , \text{g/mol} \)
B. \( 500 , \text{g/mol} \)
C. \( 750 , \text{g/mol} \)
D. \( 1000 , \text{g/mol} \)
Question 5
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 C6H12O6(s) at 298 K.
A. \( -2800 , \text{kJ/mol} \)
B. \( -2900 , \text{kJ/mol} \)
C. \( -3000 , \text{kJ/mol} \)
D. \( -3100 , \text{kJ/mol} \)
Question 6
A mixture of 2.0 g of benzene and 3.0 g of toluene is heated to produce a \single product. What is the empirical formula of the product?
A. C6H6
B. C7H8
C. C8H10
D. C9H12
Question 7
The energy change associated with the formation of a mole of water vapor at 100°C and 1 atm is -40.7 kJ/mol. What is the s\tandard enthalpy of vaporization of water at this temperature?
A. 40.7 kJ/mol
B. -40.7 kJ/mol
C. 80.7 kJ/mol
D. -80.7 kJ/mol
Question 8
Determine the number of moles of carbon dioxide gas produced when 2.5 g of calcium carbonate is decomposed at cons\tant pressure and temperature.
A. 0.05 mol
B. 0.1 mol
C. 0.15 mol
D. 0.2 mol
Question 9
A 2.5 M solution of HCl is titrated with 1.0 M NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.
A. ( 2.0 )
B. ( 2.5 )
C. ( 3.0 )
D. ( 3.5 )
Question 10
A 25.0 mL sample of 0.100 M HCl is added to a 50.0 mL sample of 0.0500 M NaOH. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 11
A 1.00 L flask contains 0.500 mol of CO2 at 298 K. If 0.500 mol of O2 is added to the flask, what is the partial pressure of CO2 in the resulting mixture?
A. 0.500 atm
B. 0.500 atm
C. 0.500 atm
D. 0.500 atm
Question 12
Determine the number of moles of electrons transferred during the electrolysis of 2.5 L of water at 25°C, given that the cell potential is 1.23 V and the current is 0.5 A.
A. 0.5 mol
B. 1.0 mol
C. 1.5 mol
D. 2.0 mol
Question 13
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M NaOH is used to titrate 25.0 mL of 0.100 M HCl, what is the pH of the resulting solution?
A. 7.00
B. 7.00
C. 7.00
D. 7.00
Question 14
Determine the pH of a 0.1 M solution of HCl at 25°C. The dissociation cons\tant of HCl is 1.0 × 10^\( -7 \).
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 15
At 298 K, the s\tandard enthalpy change \( ΔH^circ \) for the reaction 2NO(g) + O2(g) → 2NO2(g) is -113.1 kJ/mol. Calculate the s\tandard entropy change \( ΔS^circ \) for this reaction.
A. -145.6 J/mol*K
B. -145.6 J/mol*K
C. -145.6 J/mol*K
D. -145.6 J/mol*K

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