POST UTME CHRISTOPHER UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A solution contains $0.5 , M$ $NaCl$ and $0.2 , M$ $CaCl_2$. What is the total concentration of ions in the solution?
A. 0.7 M
B. 0.8 M
C. 0.9 M
D. 1.0 M
Question 2
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 3
A solution of $H_2SO_4$ is electrolyzed u\sing a platinum electrode. The electrolysis is carried out in a cell with a salt bridge. If the electrolysis is continued for a long time, what will be the final product at the cathode?
A. H_2
B. O_2
C. SO_2
D. SO_3
Question 4
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 500. What is the molar mass of the repeating unit?
A. 100 g/mol
B. 50 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 5
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 6
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 7
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 8
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 9
The pH of a 0.1 M solution of HCl is 1. What is the concentration of H^+ ions in the solution?
A. 0.1 M
B. 0.01 M
C. 0.001 M
D. 0.0001 M
Question 10
The s\tandard electrode potential of the cell is 0.80 V. If the cell is connected to a 12.0 V power source, what is the cell potential?
A. 0.80 V
B. 1.20 V
C. 1.60 V
D. 2.00 V
Question 11
A 2.00 L flask contains 0.500 atm of CO(g) and 0.750 atm of H2(g) at 25°C. What is the partial pressure of CO(g) if 0.250 atm of H2(g) is removed?
A. 0.375 atm
B. 0.500 atm
C. 0.625 atm
D. 0.750 atm
Question 12
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 13
A solution of K2Cr2O7 is reduced by SnCl2 in acidic medium to form a green precipitate. What is the name of the green precipitate?
A. Cr(OH)3
B. Cr(OH)2
C. Cr(OH)4-
D. Cr(OH)3·Sn(OH)2
Question 14
The s\tandard enthalpy of formation \( ΔH^circ_f \) of CO_2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -111.5 kJ/mol
C. -112.5 kJ/mol
D. -113.5 kJ/mol
Question 15
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

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