Practice post utme caleb university chemistry 2020 Past Questions

Question 1

Determine the pH of a 0.1 M solution of HCl.

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

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Question 2

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 1.8 g, calculate the percentage yield of the metal oxide.

A. 40%

Correct B. 50%

C. 60%

D. 70%

Correct Answer: B

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Question 3

The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.5 mol of C6H12O6(s) at 298 K.

Correct A. -1764.75 kJ

B. -1764.85 kJ

C. -1764.95 kJ

D. -1765.05 kJ

Correct Answer: A

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Question 4

A 0.1 M solution of NaOH is titrated with 0.1 M HCl. If 25 mL of HCl is required to reach the equivalence point, calculate the volume of NaOH required to reach the equivalence point.

A. 25 mL

Correct B. 50 mL

C. 75 mL

D. 100 mL

Correct Answer: B

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Question 5

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

Correct A. Burette

B. Beaker

C. Conical flask

D. Burette and beaker

Correct Answer: A

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Question 6

At 298 K, 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 (CH4(g)) at the same temperature.

Correct A. -890.3 kJ/mol

B. -890.4 kJ/mol

C. -890.5 kJ/mol

D. -890.6 kJ/mol

Correct Answer: A

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Question 7

The s\tandard Gibbs free energy of formation of a compound is -50.5 kJ/mol at 298 K. What is the equilibrium cons\tant (K) for the reaction at the same temperature?

A. 1.0

B. 10.0

Correct C. 100.0

D. 1000.0

Correct Answer: C

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Question 8

A 2.5 M solution of NaOH is prepared by dissolving 12.5 g of NaOH in 1 L of water. What is the concentration of OH- ions in the solution?

A. 0.5 M

B. 1.0 M

C. 2.0 M

Correct D. 2.5 M

Correct Answer: D

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Question 9

A 1.0 L flask contains 0.5 mol of CO2 at 298 K. What is the partial pressure of CO2 in the flask?

A. 0.5 atm

Correct B. 1.0 atm

C. 2.0 atm

D. 5.0 atm

Correct Answer: B

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Question 10

A 2.0 M solution of HCl is prepared by dissolving 40.0 g of HCl in 1 L of water. What is the concentration of H+ ions in the solution?

A. 1.0 M

Correct B. 2.0 M

C. 4.0 M

D. 8.0 M

Correct Answer: B

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Question 11

The polymerization of styrene to form polystyrene is an example of a ______ reaction.

A. chain-growth

B. step-growth

C. condensation

Correct D. addition

Correct Answer: D

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Question 12

The solubility of a gas in a liquid is given by ______ law.

Correct A. Henry's

B. Dalton's

C. Avogadro's

D. Raoult's

Correct Answer: A

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Question 13

The reaction of nitrogen dioxide with water to form nitric acid is an example of a ______ reaction.

Correct A. oxidation-reduction

B. acid-base

C. precipitation

D. neutralization

Correct Answer: A

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Question 14

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

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 separate the titrant and analyte

Correct Answer: A

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Question 15

The rate of diffusion of a gas in a liquid is given by ______ equation.

Correct A. Fick's first law

B. Fick's second law

C. Henry's law

D. Avogadro's law

Correct Answer: A

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Question 16

At 25°C, the equilibrium cons\tant (Kp) for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g) is 0.036. Calculate the partial pressure of NH3(g) when the partial pressures of N2(g) and H2(g) are 0.15 atm and 0.45 atm, respectively.

A. 0.012 atm

B. 0.024 atm

Correct C. 0.036 atm

D. 0.048 atm

Correct Answer: C

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Question 17

A 2.50 M solution of HCl is titrated with 0.500 M NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?

A. 1.00

Correct B. 2.00

C. 3.00

D. 4.00

Correct Answer: B

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Question 18

A metal (X) reacts with dilute HCl to produce a gas that gives a brown ring test with ammonia. Identify the metal.

Correct A. Cu

B. Fe

C. Zn

D. Mg

Correct Answer: A

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Question 19

The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.00 mol of C(s) at 298 K.

A. -393.5 kJ

Correct B. -393.5 kJ/mol

C. -393.5 kJ/mol

D. -393.5 kJ/mol

Correct Answer: B

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Question 20

A 1.00 M solution of H2SO4 is titrated with 0.500 M NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?

A. 1.00

Correct B. 2.00

C. 3.00

D. 4.00

Correct Answer: B

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Question 21

A solution of 0.1 M HCl is titrated with 0.1 M NaOH. The initial pH of the solution is 1. If 25 mL of NaOH is added, the pH increases to 2. What is the pH of the solution after the addition of 50 mL of NaOH?

A. 3

B. 4

Correct C. 5

D. 6

Correct Answer: C

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Question 22

The solubility of a salt, AB, in water is 0.1 g/100 mL at 25°C. If 1 g of the salt is dissolved in 100 mL of water, what is the concentration of the solution in terms of molarity?

A. 0.01 M

Correct B. 0.1 M

C. 1 M

D. 10 M

Correct Answer: B

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Question 23

A catalyst is added to a reaction mixture containing 1 M H2 and 1 M I2. The reaction is first-order with respect to H2 and second-order with respect to I2. If the initial rate of reaction is 0.1 M/s, what is the rate of reaction after 10 minutes?

A. 0.05 M/s

B. 0.1 M/s

Correct C. 0.2 M/s

D. 0.5 M/s

Correct Answer: C

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Question 24

A sample of a gas has a volume of 2 L at 25°C and 1 atm. What is the volume of the gas at 50°C and 2 atm?

A. 1 L

B. 2 L

C. 4 L

Correct D. 8 L

Correct Answer: D

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Question 25

A solution of 0.1 M HCl is titrated with 0.1 M NaOH. The initial pH of the solution is 1. If 25 mL of NaOH is added, the pH increases to 2. What is the pH of the solution after the addition of 50 mL of NaOH?

A. 3

B. 4

Correct C. 5

D. 6

Correct Answer: C

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