Practice post utme covenant university chemistry 2019 Past Questions

Question 1

A sample of an ideal gas is heated from 300 K to 400 K at cons\tant volume. Calculate the change in internal energy (ΔU) of the gas.

Correct A. 0 J

B. 1000 J

C. 2000 J

D. 3000 J

Correct Answer: A

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Question 2

The reaction of an alkanol with a strong acid produces a salt and water. Write the balanced chemical equation for the reaction between ethanol (C2H5OH) and hydrochloric acid (HCl).

Correct A. C2H5OH + HCl → C2H5Cl + H2O

B. C2H5OH + HCl → C2H5OHCl + H2

C. C2H5OH + HCl → C2H5OH2 + HCl

D. C2H5OH + HCl → C2H5Cl2 + H2O

Correct Answer: A

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Question 3

A metal alloy is composed of 80% copper and 20% zinc. If a sample of the alloy weighs 100 g, calculate the mass of copper in the sample.

Correct A. 80 g

B. 60 g

C. 40 g

D. 20 g

Correct Answer: A

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Question 4

A sample of nitrogen gas is collected over water at a temperature of 25°C and a pressure of 1 atm. If the volume of the gas is 2.5 L, calculate the partial pressure of the nitrogen gas.

Correct A. 0.95 atm

B. 1.05 atm

C. 1.10 atm

D. 1.15 atm

Correct Answer: A

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Question 5

A solution of sulfuric acid (H2SO4) is prepared by dissolving 50 g of the acid in 100 mL of water. Calculate the molarity of the solution.

A. 1.0 M

Correct B. 2.0 M

C. 3.0 M

D. 4.0 M

Correct Answer: B

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Question 6

A metal oxide, M2O3, is formed by the reaction of a metal, M, with oxygen. If 2.5 g of M2O3 is obtained from 3.2 g of M, calculate the percentage yield of the reaction.

A. 60%

Correct B. 70%

C. 80%

D. 90%

Correct Answer: B

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Question 7

The diagram below shows the atomic structure of a metal atom.

A. The metal atom has 2 valence electrons.

B. The metal atom has 3 valence electrons.

Correct C. The metal atom has 4 valence electrons.

D. The metal atom has 5 valence electrons.

Correct Answer: C

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Question 8

A solution of NaOH is prepared by dissolving 25 g of NaOH in 100 g of water. Calculate the molarity of the solution.

A. 0.5 M

Correct B. 1.0 M

C. 1.5 M

D. 2.0 M

Correct Answer: B

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Question 9

The diagram below shows a titration setup.

A. The burette contains the acid.

Correct B. The burette contains the base.

C. The beaker contains the acid.

D. The beaker contains the base.

Correct Answer: B

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Question 10

A metal, M, reacts with oxygen to form a metal oxide, MO. If 2.5 g of M is obtained from 3.2 g of MO, calculate the percentage yield of the reaction.

A. 60%

B. 70%

C. 80%

Correct D. 90%

Correct Answer: D

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Question 11

Determine the number of moles of $\text{O}_2$ produced when 2.50 g of $\text{KClO}_3$ is decomposed according to the equation: $\text{KClO}_3(s) \rightarrow \text{KCl}(s) + \frac{3}{2}\text{O}_2(g)$

A. 0.0100 mol

Correct B. 0.0150 mol

C. 0.0200 mol

D. 0.0250 mol

Correct Answer: B

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Question 12

A 0.500 M solution of $\text{H}_2SO_4$ is titrated with 0.500 M $\text{NaOH}$. If 25.0 mL of $\text{NaOH}$ is required to reach the equivalence point, calculate the number of moles of $\text{H}_2SO_4$ present in 50.0 mL of the solution.

A. 0.0100 mol

B. 0.0150 mol

Correct C. 0.0200 mol

D. 0.0250 mol

Correct Answer: C

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Question 13

A 0.500 M solution of $\text{H}_2SO_4$ is titrated with 0.500 M $\text{NaOH}$. If 25.0 mL of $\text{NaOH}$ is required to reach the equivalence point, calculate the number of moles of $\text{H}_2SO_4$ present in 50.0 mL of the solution.

A. 0.0100 mol

B. 0.0150 mol

Correct C. 0.0200 mol

D. 0.0250 mol

Correct Answer: C

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Question 14

A 0.500 M solution of $\text{H}_2SO_4$ is titrated with 0.500 M $\text{NaOH}$. If 25.0 mL of $\text{NaOH}$ is required to reach the equivalence point, calculate the number of moles of $\text{H}_2SO_4$ present in 50.0 mL of the solution.

A. 0.0100 mol

B. 0.0150 mol

Correct C. 0.0200 mol

D. 0.0250 mol

Correct Answer: C

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Question 15

A 0.500 M solution of $\text{H}_2SO_4$ is titrated with 0.500 M $\text{NaOH}$. If 25.0 mL of $\text{NaOH}$ is required to reach the equivalence point, calculate the number of moles of $\text{H}_2SO_4$ present in 50.0 mL of the solution.

A. 0.0100 mol

B. 0.0150 mol

Correct C. 0.0200 mol

D. 0.0250 mol

Correct Answer: C

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Question 16

A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If the initial volume of the acid solution is 50 mL and the equivalence point is reached at 100 mL, calculate the pH of the solution at the equivalence point.

Correct A. 7

B. 10

C. 14

D. 12

Correct Answer: A

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Question 17

The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). If 25.0 g of zinc metal is added to 250 mL of 0.100 M CuSO4 solution, what is the limiting reac\tant?

Correct A. Zn

B. CuSO4

C. ZnSO4

D. Cu

Correct Answer: A

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Question 18

A 2.0 M solution of sodium hydroxide (NaOH) is mixed with a 1.0 M solution of hydrochloric acid (HCl). If 50 mL of the NaOH solution is added to 100 mL of the HCl solution, what is the pH of the resulting solution?

A. 2

Correct B. 3

C. 4

D. 5

Correct Answer: B

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Question 19

A 0.1 M solution of a weak base B is titrated with 0.1 M HCl. If the initial volume of the base solution is 50 mL and the equivalence point is reached at 100 mL, calculate the pH of the solution at the equivalence point.

Correct A. 7

B. 10

C. 14

D. 12

Correct Answer: A

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Question 20

The reaction between aluminum metal and iron(III) chloride solution is represented by the equation: 2Al(s) + 3FeCl3(aq) → 2AlCl3(aq) + 3Fe(s). If 25.0 g of aluminum metal is added to 250 mL of 0.100 M FeCl3 solution, what is the limiting reac\tant?

Correct A. Al

B. FeCl3

C. AlCl3

D. Fe

Correct Answer: A

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Question 21

Determine the pH of a 0.1 M solution of HCl, given that the dissociation cons\tant of HCl is 10^$ -7 $ and the concentration of HCl is 0.1 M.

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

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Question 22

A diagram of a titration setup is shown below. If 25 mL of 0.1 M NaOH is added to 25 mL of 0.1 M HCl, what is the pH of the resulting solution?

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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Question 23

The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of H2O(l) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol and the s\tandard enthalpy of formation of O2(g) is 0 kJ/mol.

Correct A. -285.8

B. -285.9

C. -285.7

D. -285.6

Correct Answer: A

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Question 24

A diagram of a simple black and white chemistry apparatus showing a titration setup is shown below.

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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Question 25

The s\tandard enthalpy of formation of NH3(g) is -45.9 kJ/mol. Calculate the s\tandard enthalpy of formation of N2(g) if the s\tandard enthalpy of formation of H2(g) is 0 kJ/mol.

Correct A. 0

B. -45.9

C. -45.8

D. -45.7

Correct Answer: A

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