POST UTME ABU 2021 Chemistry | Objective

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Question 1
Determine the number of moles of $\text{CO}_2$ produced when 2.50 g of $\text{CaCO}_3$ is decomposed at cons\tant pressure and temperature.
A. 0.0500 mol
B. 0.100 mol
C. 0.150 mol
D. 0.200 mol
Question 2
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO?
A. -110.5 kJ/mol
B. -210.5 kJ/mol
C. -310.5 kJ/mol
D. -410.5 kJ/mol
Question 3
A 1.00 M solution of NH3 is mixed with a 1.00 M solution of HCl. Calculate the concentration of NH4Cl in the resulting solution.
A. 1.00 M
B. 0.50 M
C. 0.25 M
D. 0.10 M
Question 4
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol, and ΔHf(C(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 5
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of H2O(l) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and that of CO(g) is -110.5 kJ/mol?
A. -285.8
B. -285.6
C. -285.4
D. -285.2
Question 6
The solubility product cons\tant (Ksp) for AgCl is 1.8 x 10^-10. Calculate the molar solubility of AgCl in a 0.10 M NaCl solution.
A. 1.00 x 10^-5 M
B. 1.50 x 10^-5 M
C. 2.00 x 10^-5 M
D. 2.50 x 10^-5 M
Question 7
A 0.1000 M solution of $\text{HCl}$ is mixed with a 0.1000 M solution of $\text{NaOH}$. What is the concentration of $\text{HCl}$ after the reaction is complete?
A. 0.0500 M
B. 0.0750 M
C. 0.100 M
D. 0.125 M
Question 8
A 2.50 g sample of nitrogen gas is collected over water at 25°C and 1.00 atm. Calculate the volume of the gas, in liters, assuming that the partial pressure of nitrogen is 0.950 atm.
A. 1.50 L
B. 2.00 L
C. 2.50 L
D. 3.00 L
Question 9
A 0.500 M solution of NaCl is electrolyzed u\sing a current of 2.50 A. Calculate the mass of Cl2(g) produced at the anode after 2.00 hours.
A. 0.250 g
B. 0.500 g
C. 1.00 g
D. 1.50 g
Question 10
A sample of a non-metallic element has a mass of 2.5 g and a volume of 2.0 cm^3. If the density of the element is 2.5 g/cm^3, what is its molar mass?
A. 10
B. 20
C. 30
D. 40
Question 11
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. -110.5 kJ/mol
C. -110.5 kJ/mol
D. -110.5 kJ/mol
Question 12
A 2.5 M solution of HCl is mixed with a 2.5 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 13
The reaction between sulfuric acid and sodium hydroxide is a classic example of a neutralization reaction. Write the balanced chemical equation for this reaction, including the state of each subs\tance.
A. H2SO4 (aq) + 2NaOH (aq) → Na2SO4 (aq) + 2H2O (l)
B. H2SO4 (l) + 2NaOH (aq) → Na2SO4 (s) + 2H2O (g)
C. H2SO4 (aq) + NaOH (s) → Na2SO4 (aq) + H2O (l)
D. H2SO4 (l) + NaOH (aq) → Na2SO4 (aq) + H2O (l)
Question 14
A 50.0 mL sample of a solution containing 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 25.0 mL
B. 50.0 mL
C. 75.0 mL
D. 100 mL
Question 15
A sample of oxygen gas is collected over water at 25°C and 1.00 atm. If the partial pressure of oxygen is 0.800 atm, what is the volume of the gas, in liters?
A. 1.00 L
B. 1.25 L
C. 1.50 L
D. 2.00 L

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