Practice Post UTME RHEMA UNIVERSITY chemistry 2022 Past Questions

Question 1

The rate cons\tant (k) for a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the rate cons\tant at 25°C is 0.05 s^\( -1 \) and at 50°C is 0.15 s^\( -1 \), calculate the activation energy (Ea) of the reaction in kJ/mol.

A. 20 kJ/mol

B. 30 kJ/mol

Correct C. 40 kJ/mol

D. 50 kJ/mol

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 2

A 2.5 g sample of a metal oxide is dissolved in 50 cm^3 of 0.1 M HCl. The resulting solution is then titrated with 0.1 M NaOH. If 25 cm^3 of NaOH is required to reach the equivalence point, what is the molar mass of the metal oxide?

A. 100 g/mol

B. 150 g/mol

Correct C. 200 g/mol

D. 250 g/mol

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 3

A 10% solution of a polymer is prepared by dissolving 10 g of the polymer in 90 g of a solvent. If the density of the polymer is 1.2 g/cm^3, what is the volume of the polymer in the solution?

A. 8.3 cm^3

Correct B. 10 cm^3

C. 12 cm^3

D. 15 cm^3

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 4

A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: 2X + Cl_2 → 2XCl. If 2.5 g of X reacts with 1.5 g of Cl_2, what is the percentage yield of the reaction?

A. 80%

B. 90%

Correct C. 95%

D. 98%

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 5

A 1 M solution of a strong acid is prepared by dissolving 36.5 g of the acid in 1 dm^3 of water. If the density of the acid is 1.2 g/cm^3, what is the molar mass of the acid?

A. 100 g/mol

B. 150 g/mol

Correct C. 200 g/mol

D. 250 g/mol

Correct Answer: C

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 6

A sample of a metal oxide, M2O3, has a mass of 25.0 g. If the metal has an atomic mass of 52.0 g/mol and the oxide has a molar mass of 168.0 g/mol, what is the empirical formula of the metal oxide?

Correct A. M2O3

B. MO2

C. M2O5

D. MO3

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 7

A 1.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of the gas?

Correct A. 0.976 atm

B. 1.00 atm

C. 1.02 atm

D. 1.04 atm

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 8

A solution contains 5.00 g of NaCl in 100.0 mL of water. What is the molarity of the solution?

A. 0.500 M

Correct B. 0.750 M

C. 1.00 M

D. 1.25 M

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 9

A 2.00 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of the gas?

Correct A. 0.976 atm

B. 1.00 atm

C. 1.02 atm

D. 1.04 atm

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 10

A solution contains 10.0 g of NaOH in 100.0 mL of water. What is the molarity of the solution?

A. 1.00 M

Correct B. 1.25 M

C. 1.50 M

D. 1.75 M

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 11

Determine the number of unpaired electrons in the ground state of a neutral atom of the element with atomic number 13.

A. 4

Correct B. 2

C. 6

D. 8

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 12

A 0.5 M solution of NaCl is prepared by dissolving 25 g of NaCl in 1 L of water. What is the concentration of the solution in terms of molality?

A. 0.5 m

Correct B. 1.0 m

C. 2.0 m

D. 5.0 m

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 13

A metal M has a density of 11.5 g/cm^3 and a molar mass of 65.4 g/mol. If a 2.5 g sample of the metal is obtained from a mineral, what is the volume of the sample in cm^3?

A. 1.1 cm^3

Correct B. 2.2 cm^3

C. 3.3 cm^3

D. 4.4 cm^3

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 14

A solution contains 2.5 g of NaCl in 250 mL of water. What is the concentration of the solution in terms of molarity?

A. 0.1 M

Correct B. 0.2 M

C. 0.3 M

D. 0.4 M

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 15

A 10% solution of HCl is prepared by dissolving 10 g of HCl in 90 g of water. What is the concentration of the solution in terms of molality?

A. 0.1 m

Correct B. 1.0 m

C. 2.0 m

D. 5.0 m

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 16

A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. The pH of the solution at the equivalence point is 7.00. What is the pH of the solution at the half-equivalence point?

A. 4.00

Correct B. 5.00

C. 6.00

D. 7.00

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 17

A 2.50 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 2.00 g. What is the percentage yield of the metal oxide?

Correct A. 80.0%

B. 90.0%

C. 95.0%

D. 98.0%

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 18

A 1.00 L sample of a 0.100 M solution of a weak acid is titrated with 0.100 M NaOH. The pH of the solution at the equivalence point is 7.00. What is the pH of the solution at the half-equivalence point?

A. 4.00

Correct B. 5.00

C. 6.00

D. 7.00

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 19

A 2.50 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 2.00 g. What is the percentage yield of the metal oxide?

Correct A. 80.0%

B. 90.0%

C. 95.0%

D. 98.0%

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 20

A 1.00 L sample of a 0.100 M solution of a weak acid is titrated with 0.100 M NaOH. The pH of the solution at the equivalence point is 7.00. What is the pH of the solution at the half-equivalence point?

A. 4.00

Correct B. 5.00

C. 6.00

D. 7.00

Correct Answer: B

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 21

The reaction between sulfur dioxide and oxygen to form sulfur trioxide is catalyzed by vanadium(V) oxide. Write the balanced equation for this reaction, including the role of the catalyst.

A. \text{SO}_2 + \text{O}_2 \xrightarrow[\text{V}_2\text{O}_5]{\text{catalyst}} \text{SO}_3

B. \text{SO}_2 + \text{O}_2 \xrightarrow[\text{V}_2\text{O}_5]{\text{catalyst}} \text{SO}_2

C. \text{SO}_2 + \frac{1}{2}\text{O}_2 \xrightarrow[\text{V}_2\text{O}_5]{\text{catalyst}} \text{SO}_2

Correct D. \text{SO}_2 + \frac{1}{2}\text{O}_2 \xrightarrow[\text{V}_2\text{O}_5]{\text{catalyst}} \text{SO}_3

Correct Answer: D

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 22

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 1.8 g. Calculate the percentage yield of the metal oxide.

Correct A. 72%

B. 80%

C. 90%

D. 95%

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 23

The diagram below shows a titration setup. Identify the part labeled A.

Correct A. burette

B. pipette

C. Erlenmeyer flask

D. beaker

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 24

The reaction between sodium hydroxide and hydrochloric acid is a neutralization reaction. Write the balanced equation for this reaction.

Correct A. \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}

B. \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}_2

C. \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}_3

D. \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

Question 25

A 1.0 M solution of sodium hydroxide is titrated with a 1.0 M solution of hydrochloric acid. The volume of hydrochloric acid required to reach the equivalence point is 25 mL. Calculate the number of moles of sodium hydroxide.

Correct A. 0.025 mol

B. 0.050 mol

C. 0.075 mol

D. 0.100 mol

Correct Answer: A

Want to see the full step-by-step solution? Unlock AI Explanation & Analytics

POST UTME RHEMA UNIVERSITY 2022 Chemistry | Objective

Master the Exam!

Help others prepare! Share this practice hub: