POST UTME CRAWFORD UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.0 g sample of a metal hydroxide is heated to produce a metal oxide and water vapor. The mass of the metal oxide produced is 1.5 g. Calculate the mass of water vapor produced.
A. 0.5 g
B. 1.0 g
C. 1.5 g
D. 2.0 g
Question 2
A 1.0 L solution of 0.1 M HCl is mixed with 1.0 L of 0.1 M NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 3
A solution of sodium hydroxide (NaOH) is titrated with a solution of hydrochloric acid (HCl). The reaction is as follows: NaOH + HCl → NaCl + H2O. If 20.0 cm3 of 0.1 mol dm-3 NaOH is required to react with 30.0 cm3 of 0.2 mol dm-3 HCl, calculate the number of moles of HCl present in the solution.
A. 0.05 mol
B. 0.1 mol
C. 0.2 mol
D. 0.5 mol
Question 4
A solution of potassium permanganate (KMnO4) is titrated with a solution of sodium oxalate (Na2C2O4). The reaction is as follows: 2KMnO4 + 5Na2C2O4 + H2SO4 → K2SO4 + 2MnSO4 + 10NaC2O4 + 2H2O. If 25.0 cm3 of 0.1 mol dm-3 KMnO4 is required to react with 20.0 cm3 of 0.2 mol dm-3 Na2C2O4, calculate the number of moles of Na2C2O4 present in the solution.
A. 0.05 mol
B. 0.1 mol
C. 0.2 mol
D. 0.5 mol
Question 5
Determine the s\tandard enthalpy of formation of NO2(g) from the following data: ΔHf(N2(g)) = 0 kJ/mol, ΔHf(O2(g)) = 0 kJ/mol, ΔHf(NO(g)) = 91.3 kJ/mol. The reaction is: N2(g) + 2O2(g) → 2NO2(g).
A. -339.9 kJ/mol
B. -339.8 kJ/mol
C. -339.7 kJ/mol
D. -339.6 kJ/mol
Question 6
A solution of potassium chloride (KCl) is titrated with a solution of silver nitrate (AgNO3). The reaction is as follows: 2KCl + AgNO3 → AgCl + KNO3. If 25.0 cm3 of 0.1 mol dm-3 KCl is required to react with 20.0 cm3 of 0.2 mol dm-3 AgNO3, calculate the number of moles of AgNO3 present in the solution.
A. 0.05 mol
B. 0.1 mol
C. 0.2 mol
D. 0.5 mol
Question 7
The reaction 2NO(g) + O2(g) → 2NO2(g) has a s\tandard enthalpy change of -114 kJ/mol. Calculate the s\tandard entropy change (ΔS) for the reaction.
A. -120 J/mol·K
B. -140 J/mol·K
C. -160 J/mol·K
D. -180 J/mol·K
Question 8
A 2.5 M solution of NaOH is prepared by dissolving 12.5 g of NaOH in water to make 250 mL of solution. Calculate the molarity of the solution.
A. 2.5 M
B. 3.0 M
C. 2.0 M
D. 1.5 M
Question 9
A sample of CO2(g) is collected over water at 25°C and 1 atm. If the partial pressure of CO2(g) is 0.8 atm, what is the mole \fraction of CO2(g) in the gas mixture?
A. 0.8
B. 0.7
C. 0.6
D. 0.5
Question 10
The s\tandard Gibbs free energy change for the reaction 2Ag+ + Cu → 2Ag + Cu2+ is -120 kJ/mol. Calculate the equilibrium cons\tant (K) for the reaction.
A. 10^\( -6 \)
B. 10^\( -12 \)
C. 10^\( -18 \)
D. 10^\( -24 \)
Question 11
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is present initially, what mass of the subs\tance will remain after 10 years?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g
Question 12
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 1.5 g. Calculate the mass of carbon dioxide gas produced.
A. 0.5 g
B. 1.0 g
C. 1.5 g
D. 2.0 g
Question 13
A 1.0 L solution of 0.1 M HCl is mixed with 1.0 L of 0.1 M NaOH. What is the concentration of the resulting solution?
A. 0.1 M
B. 0.05 M
C. 0.01 M
D. 0.005 M
Question 14
A solution containing 0.1 M NH3(aq) is mixed with 0.1 M HCl(aq). If the reaction is: NH3(aq) + HCl(aq) → NH4Cl(aq), what is the concentration of NH3(aq) after the reaction is complete?
A. 0 M
B. 0.1 M
C. 0.05 M
D. 0.01 M
Question 15
A 2.0 M solution of NaOH(aq) is mixed with 1.0 M HCl(aq). If the reaction is: NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l), what is the concentration of NaOH(aq) after the reaction is complete?
A. 1.0 M
B. 0.5 M
C. 0.25 M
D. 0.1 M

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