POST UTME CHRISTOPHER UNIVERSITY 2023 Chemistry | Objective

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Question 1
A sample of 0.500 L of 0.100 M HCl(aq) is mixed with 0.500 L of 0.100 M NaOH(aq). What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 2
A solution contains 0.1 M NaCl. If 10 mL of this solution is diluted to 100 mL, what is the new concentration of NaCl?
A. 0.01 M
B. 0.1 M
C. 1 M
D. 10 M
Question 3
A 2.00 L flask contains 0.500 atm of N2(g) and 0.750 atm of O2(g) at 25°C. What is the partial pressure of O2(g) if 0.250 atm of N2(g) is removed?
A. 0.375 atm
B. 0.500 atm
C. 0.625 atm
D. 0.750 atm
Question 4
Calculate the s\tandard enthalpy change \( ΔH^circ \) for the reaction: 2Al(s) + Fe_2O_3(s) → 2Fe(s) + Al_2O_3(s). Given: ΔH^circ_f\( Al_2O_3\( s \ \)) = -1675.7 kJ/mol, ΔH^circ_f\( Fe_2O_3\( s \ \)) = -825.4 kJ/mol, ΔH^circ_f(Al(s)) = 0 kJ/mol, ΔH^circ_f(Fe(s)) = 0 kJ/mol.
A. -1751.1 kJ/mol
B. -1751.9 kJ/mol
C. -1750.5 kJ/mol
D. -1752.3 kJ/mol
Question 5
Determine the number of moles of AgCl(s) that will precipitate from a solution containing 2.50 x 10^-3 M AgNO3(aq) and 1.00 x 10^-2 M NaCl(aq) when the reaction reaches equilibrium.
A. 0.00125 mol
B. 0.00250 mol
C. 0.00500 mol
D. 0.00750 mol
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -393.5 kJ/mol
C. -110.5 kJ/mol + 393.5 kJ/mol
D. 393.5 kJ/mol
Question 7
A polymer is a long chain of repeating units called monomers. What is the name of the process by which a polymer is formed from its monomers?
A. Polymerization
B. Depolymerization
C. Condensation reaction
D. Addition reaction
Question 8
A 2.5 g sample of a metal oxide is heated in a crucible until it loses 0.5 g of oxygen. Calculate the molar mass of the metal oxide, given that the molar mass of oxygen is 16 g/mol.
A. 100 g/mol
B. 120 g/mol
C. 140 g/mol
D. 160 g/mol
Question 9
A solution contains 0.1 M NaCl. If 10 mL of this solution is diluted to 100 mL, what is the new concentration of NaCl?
A. 0.01 M
B. 0.1 M
C. 1 M
D. 10 M
Question 10
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 200. What is the molar mass of the repeating unit?
A. 250 g/mol
B. 500 g/mol
C. 750 g/mol
D. 1000 g/mol
Question 11
A metal oxide has the formula M2O3. What is the oxidation state of the metal?
A. +3
B. +5
C. +6
D. +7
Question 12
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. The pH of the solution after the addition of 25.0 mL of NaOH is 8.50. What is the concentration of the NaOH solution?
A. 0.100 M
B. 0.0500 M
C. 0.0250 M
D. 0.0125 M
Question 13
A 2.5 g sample of a metal oxide is heated in a crucible until it loses 0.5 g of oxygen. Calculate the molar mass of the metal oxide, given that the molar mass of oxygen is 16 g/mol.
A. 100 g/mol
B. 120 g/mol
C. 140 g/mol
D. 160 g/mol
Question 14
A solution contains 0.1 M NaCl. If 10 mL of this solution is diluted to 100 mL, what is the new concentration of NaCl?
A. 0.01 M
B. 0.1 M
C. 1 M
D. 10 M
Question 15
The diagram below shows a graph of $pH$ versus $[H^+]$.
A. The $pH$ increases as $[H^+]$ increases.
B. The $pH$ decreases as $[H^+]$ increases.
C. The $pH$ remains cons\tant as $[H^+]$ increases.
D. The $pH$ decreases as $[H^+]$ decreases.

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