Exam Body

Year

Subject

Paper Type

POST UTME RHEMA UNIVERSITY 2021 Chemistry | Objective

Are you preparing for POST UTME RHEMA UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2021 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1

Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g), given that the initial concentrations of NO and O2 are 0.1 M and 0.05 M, respectively, and the rate of reaction is 0.02 M/s after 10 minutes.

A. \( k = 0.1 , \text{M}^{-1} , \text{s}^{-1} \)

Correct B. \( k = 0.2 , \text{M}^{-1} , \text{s}^{-1} \)

C. \( k = 0.3 , \text{M}^{-1} , \text{s}^{-1} \)

D. \( k = 0.4 , \text{M}^{-1} , \text{s}^{-1} \)

Correct Answer: B

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

Question 2

A polymer has a molecular weight of 50000 g/mol and a degree of polymerization of 200. Calculate the molar mass of the repeating unit.

A. \( 250 , \text{g/mol} \)

Correct B. \( 500 , \text{g/mol} \)

C. \( 750 , \text{g/mol} \)

D. \( 1000 , \text{g/mol} \)

Correct Answer: B

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

Question 3

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 C6H12O6(s) at 298 K.

A. \( -2800 , \text{kJ/mol} \)

B. \( -2900 , \text{kJ/mol} \)

Correct C. \( -3000 , \text{kJ/mol} \)

D. \( -3100 , \text{kJ/mol} \)

Correct Answer: C

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

Question 4

A 2.5 M solution of HCl is titrated with 1.0 M NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.

A. ( 2.0 )

B. ( 2.5 )

Correct C. ( 3.0 )

D. ( 3.5 )

Correct Answer: C

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

Question 5

A cell consists of a Zn anode and a Cu cathode. The s\tandard electrode potentials are E°\( Zn2+/Zn \) = -0.76 V and E°\( Cu2+/Cu \) = +0.34 V. Calculate the cell potential.

A. \( -1.1 , \text{V} \)

Correct B. \( -1.2 , \text{V} \)

C. \( -1.3 , \text{V} \)

D. \( -1.4 , \text{V} \)

Correct Answer: B

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

Question 6

Determine the number of moles of carbon dioxide gas produced when 2.5 g of calcium carbonate is decomposed at cons\tant pressure and temperature.

A. 0.05 mol

Correct B. 0.1 mol

C. 0.15 mol

D. 0.2 mol

Correct Answer: B

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

Question 7

A sample of 0.5 M hydrochloric acid is titrated with 0.2 M sodium hydroxide. What is the pH of the solution after 25 mL of sodium hydroxide has been added?

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

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

Question 8

A mixture of 2.0 g of benzene and 3.0 g of toluene is heated to produce a \single product. What is the empirical formula of the product?

A. C6H6

Correct B. C7H8

C. C8H10

D. C9H12

Correct Answer: B

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

Question 9

A solution of 0.1 M sodium chloride is prepared by dissolving 10 g of sodium chloride in 1 L of water. What is the concentration of the solution in g/L?

Correct A. 10 g/L

B. 20 g/L

C. 30 g/L

D. 40 g/L

Correct Answer: A

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

Question 10

A sample of 2.0 g of glu\cose is dissolved in 100 mL of water. What is the concentration of the solution in g/100 mL?

A. 2 g/100 mL

Correct B. 4 g/100 mL

C. 6 g/100 mL

D. 8 g/100 mL

Correct Answer: B

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

Question 11

The reaction of zinc metal with copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). If 2.50 g of zinc metal is added to 250 mL of 0.100 M copper(II) sulfate solution, what is the limiting reac\tant?

Correct A. Zn(s)

B. CuSO4(aq)

C. ZnSO4(aq)

D. Cu(s)

Correct Answer: A

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

Question 12

A sample of nitrogen gas occupies a volume of 2.50 L at a pressure of 1.50 atm and a temperature of 298 K. What is the new volume of the gas if the pressure is increased to 3.00 atm and the temperature is decreased to 273 K?

A. 1.00 L

B. 1.50 L

Correct C. 2.00 L

D. 2.50 L

Correct Answer: C

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

Question 13

The diagram below shows a titration setup. What is the purpose of the burette?

Correct A. To measure the volume of the titrant

B. To measure the volume of the analyte

C. To mix the titrant and analyte

D. To measure the pH of the solution

Correct Answer: A

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

Question 14

A solution contains 0.100 M sodium chloride (NaCl) and 0.0500 M sodium sulfate (Na2SO4). What is the concentration of chloride ions \( Cl- \) in the solution?

A. 0.0500 M

Correct B. 0.0750 M

C. 0.100 M

D. 0.125 M

Correct Answer: B

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

Question 15

A sample of oxygen gas occupies a volume of 1.50 L at a pressure of 2.00 atm and a temperature of 298 K. What is the new volume of the gas if the pressure is decreased to 1.00 atm and the temperature is increased to 323 K?

A. 1.00 L

Correct B. 1.25 L

C. 1.50 L

D. 2.00 L

Correct Answer: B

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

Question 16

The energy change associated with the formation of a mole of water vapor at 100°C and 1 atm is -40.7 kJ/mol. What is the s\tandard enthalpy of vaporization of water at this temperature?

A. 40.7 kJ/mol

Correct B. -40.7 kJ/mol

C. 80.7 kJ/mol

D. -80.7 kJ/mol

Correct Answer: B

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

Question 17

A 2.0 M solution of NaCl is prepared by dissolving 40.0 g of NaCl in 1.0 L of water. What is the concentration of Cl- ions in the solution?

A. 2.0 M

Correct B. 1.0 M

C. 0.5 M

D. 4.0 M

Correct Answer: B

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

Question 18

A sample of gas occupies a volume of 2.5 L at a pressure of 3.0 atm. What is the pressure of the gas if its volume is reduced to 1.0 L?

Correct A. 6.0 atm

B. 3.0 atm

C. 1.5 atm

D. 0.5 atm

Correct Answer: A

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

Question 19

A 10.0 g sample of a subs\tance is dissolved in 100.0 mL of water. What is the molarity of the solution?

A. 1.0 M

Correct B. 0.5 M

C. 2.0 M

D. 4.0 M

Correct Answer: B

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

Question 20

A 5.0 L sample of a gas is collected over water at a temperature of 25°C and a pressure of 1.0 atm. What is the partial pressure of the gas?

Correct A. 0.5 atm

B. 1.0 atm

C. 1.5 atm

D. 2.0 atm

Correct Answer: A

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

Question 21

Determine the number of moles of electrons transferred during the electrolysis of 2.5 L of water at 25°C, given that the cell potential is 1.23 V and the current is 0.5 A.

A. 0.5 mol

Correct B. 1.0 mol

C. 1.5 mol

D. 2.0 mol

Correct Answer: B

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

Question 22

A metal M reacts with chlorine gas to form a white solid product. The reaction is as follows: M + Cl2 → MX2. If 2.5 g of M is reacted with 1.5 g of Cl2, what is the limiting reac\tant?

Correct A. M

B. Cl2

C. MX2

D. Neither M nor Cl2 is the limiting reac\tant.

Correct Answer: A

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

Question 23

A solution of 0.1 M HCl is mixed with a solution of 0.1 M NaOH. What is the pH of the resulting solution?

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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

Question 24

A sample of a metal M has a mass of 25 g. If the density of the metal is 8.5 g/cm3, what is the volume of the metal?

A. 2.9 cm3

Correct B. 3.0 cm3

C. 3.1 cm3

D. 3.2 cm3

Correct Answer: B

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

Question 25

A solution of 0.1 M HCl is mixed with a solution of 0.1 M NaOH. What is the concentration of the resulting solution?

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

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows

Help others prepare! Share this practice hub:

Chat with Support