POST UTME RSU 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of a solid has a molar mass of 100 g/mol. What is the density of the solid?
A. 1 g/cm^3
B. 2 g/cm^3
C. 3 g/cm^3
D. 4 g/cm^3
Question 2
A 10.0 g sample of a hydrocarbon is heated to produce a non-metallic element and carbon dioxide gas. If the mass of the non-metallic element produced is 7.5 g, calculate the percentage yield of the non-metallic element.
A. 75%
B. 80%
C. 85%
D. 90%
Question 3
The reaction of sodium chloride with silver nitrate produces a precipitate of silver chloride. What is the balanced equation for this reaction?
A. \text{NaCl} + \text{AgNO}_3 \rightarrow \text{AgCl} + \text{NaNO}_3
B. \text{NaCl} + \text{AgNO}_3 \rightarrow \text{Ag}_2\text{Cl}_2 + \text{NaNO}_3
C. \text{NaCl} + \text{AgNO}_3 \rightarrow \text{AgCl} + \text{Na}_2\text{O}
D. \text{NaCl} + \text{AgNO}_3 \rightarrow \text{AgCl} + \text{Na}_2\text{O}_3
Question 4
A 2.0 M solution of hydrochloric acid (HCl) is mixed with a 1.0 M solution of sodium hydroxide (NaOH). If 50 mL of HCl is added to 100 mL of NaOH, what is the resulting pH?
A. 1
B. 2
C. 3
D. 4
Question 5
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 6
The reaction between hydrogen peroxide (H2O2) and potassium iodide (KI) is a first-order reaction. The rate cons\tant (k) is 0.05 min^-1. If the initial concentration of H2O2 is 0.1 M, what is the concentration of H2O2 after 10 minutes?
A. 0.01 M
B. 0.05 M
C. 0.1 M
D. 0.2 M
Question 7
A 10 mL sample of a colloidal solution is centrifuged for 10 minutes. The superna\tant is then titrated with 0.1 M HCl. The pH of the superna\tant is 7. What is the concentration of the colloidal particles?
A. 0.01 g/L
B. 0.1 g/L
C. 1 g/L
D. 10 g/L
Question 8
A 5.0 g sample of a non-metallic oxide is heated to produce a non-metallic element and oxygen gas. If the mass of the non-metallic element produced is 3.2 g, calculate the percentage yield of the non-metallic element.
A. 80%
B. 85%
C. 90%
D. 95%
Question 9
A 2.00 M solution of HCl is mixed with 20.0 mL of 0.100 M NaOH. If the reaction is complete, what is the concentration of the resulting solution?
A. 0.0125 M
B. 0.0250 M
C. 0.0500 M
D. 0.100 M
Question 10
Determine the pH of a solution containing 0.1 M HCl and 0.1 M NaOH, assuming complete neutralization.
A. 1
B. 7
C. 10
D. 14
Question 11
The s\tandard enthalpy of formation of NH3(g) is -45.9 kJ/mol. What is the s\tandard enthalpy of formation of N2H4(l)?
A. -50.6 kJ/mol
B. -50.6 kJ/mol
C. -50.6 kJ/mol
D. -50.6 kJ/mol
Question 12
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 2.1 g, calculate the percentage yield of the metal oxide.
A. 90%
B. 92%
C. 95%
D. 98%
Question 13
A 50 mL sample of a solution containing 0.1 M HCl and 0.1 M NaOH is titrated with 0.1 M NaOH. The pH of the solution after the addition of 20 mL of NaOH is 7. What is the concentration of the resulting solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 14
A sample of a metal carbonate (M2CO3) is heated to produce a metal oxide (M2O) and carbon dioxide gas. If 2.50 g of the metal carbonate is heated to produce 1.25 g of the metal oxide, what is the molar mass of the metal carbonate?
A. 100 g/mol
B. 100 g/mol
C. 100 g/mol
D. 100 g/mol
Question 15
A solution of sodium hydroxide (NaOH) is mixed with a solution of hydrochloric acid (HCl) in a 1:1 ratio. If 25 mL of the NaOH solution has a concentration of 0.5 M, calculate the number of moles of HCl required to react with the NaOH.
A. 0.125 mol
B. 0.25 mol
C. 0.5 mol
D. 1 mol

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