POST UTME UNIPORT 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of iron(II) sulfate is heated to produce iron(III) oxide and sulfur trioxide. What is the balanced chemical equation for this reaction?
A. \( 2FeSO_4\( s \ \) \rightarrow Fe_2O_3(s) + SO_3(g) )
B. \( FeSO_4\( s \ \) \rightarrow Fe_2O_3(s) + SO_3(g) )
C. \( 2FeSO_4\( s \ \) \rightarrow 2Fe_2O_3(s) + 2SO_3(g) )
D. \( FeSO_4\( s \ \) \rightarrow Fe_2O_3(s) + SO_2(g) )
Question 2
Determine the number of moles of oxygen gas (O2) that react with 2.5 moles of carbon monoxide (CO) in the following reaction: 2CO + O2 → 2CO2. Assume that the reaction occurs at cons\tant pressure.
A. 1.25 moles
B. 2.5 moles
C. 5 moles
D. 10 moles
Question 3
A solution contains 2.5 g of sodium chloride per 100 mL of solution. What is the molarity of the solution?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.00 M
Question 4
A 25.0 mL sample of a 0.100 M solution of sodium hydroxide (NaOH) is titrated with a 0.100 M solution of hydrochloric acid (HCl). If 25.0 mL of HCl is required to reach the equivalence point, calculate the number of moles of NaOH in the original solution.
A. 0.00250 mol
B. 0.00500 mol
C. 0.00750 mol
D. 0.0100 mol
Question 5
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. If 10 mL of NaOH is required to reach the equivalence point, what is the volume of HCl in liters?
A. 0.01 L
B. 0.1 L
C. 0.1 mL
D. 0.01 mL
Question 6
A 2.5 M solution of hydrochloric acid (HCl) is titrated with a 0.5 M solution of sodium hydroxide (NaOH). If 25 mL of the NaOH solution is required to reach the equivalence point, what is the volume of the HCl solution that was initially added?
A. 12.5 mL
B. 25 mL
C. 50 mL
D. 100 mL
Question 7
The reaction between hydrogen peroxide (H2O2) and potassium iodide (KI) is catalyzed by iodide ions \( I- \). The rate law for this reaction is given by rate = k[H2O2][I-]. If the initial concentrations of H2O2 and I- are 0.100 M and 0.0500 M, respectively, and the rate cons\tant (k) is 1.00 x 10^-3 M^-1 s^-1, calculate the initial rate of reaction.
A. 1.00 x 10^-5 M s^-1
B. 5.00 x 10^-5 M s^-1
C. 1.00 x 10^-4 M s^-1
D. 5.00 x 10^-4 M s^-1
Question 8
A 2.00 g sample of a polymer is dissolved in 100.0 mL of a solvent. If the solution has a vis\cosity of 1.50 cP, calculate the number-average molecular weight (Mn) of the polymer.
A. 5000 g/mol
B. 10000 g/mol
C. 15000 g/mol
D. 20000 g/mol
Question 9
A sample of CO2 is collected over water at a temperature of 25°C and a pressure of 1 atm. If the partial pressure of CO2 is 0.5 atm, what is the mole \fraction of CO2?
A. 0.5
B. 0.25
C. 0.75
D. 0.9
Question 10
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 methane.
A. -890.3 kJ/mol
B. -890.8 kJ/mol
C. -891.3 kJ/mol
D. -892.8 kJ/mol
Question 11
A 25 mL sample of a solution containing 0.1 M NaOH is titrated with 0.1 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 12
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, what is the value of the pre-exponential factor (A) if the rate cons\tant (k) is 0.05 s^-1?
A. 1.67 x 10^10 s^-1
B. 1.67 x 10^8 s^-1
C. 1.67 x 10^6 s^-1
D. 1.67 x 10^4 s^-1
Question 13
What is the expected product of the reaction between sulfuric acid and sodium hydroxide?
A. Sodium sulfate
B. Sulfuric acid
C. Sodium hydroxide
D. Water
Question 14
A 2.5 L flask contains 0.5 mol of an ideal gas at 27°C. Calculate the pressure of the gas in the flask.
A. 1.5 atm
B. 2.5 atm
C. 3.5 atm
D. 4.5 atm
Question 15
What is the primary difference between a saturated and an unsaturated hydrocarbon?
A. Saturated hydrocarbons have a \single bond between carbon atoms, while unsaturated hydrocarbons have multiple bonds
B. Saturated hydrocarbons have multiple bonds between carbon atoms, while unsaturated hydrocarbons have a \single bond
C. Saturated hydrocarbons are more stable than unsaturated hydrocarbons
D. Unsaturated hydrocarbons are more stable than saturated hydrocarbons

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