Quiz 1

Chemistry(Redox Reaction)

Quiz Type

Practice

Subject

Molecular Biology

Level

Level 100

Questions

10 questions

Created By

Stella Boadi

Quick Rules

Time limit: 50 minutes
Multiple attempts are not allowed
All questions must be answered to submit

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Question 1 of 10

Question 1

Basic multiple choice Remembering

What does the term 'redox reaction' refer to?

A reaction that involves the giving and taking of electrons

Correct

A reaction that only involves the formation of bonds

A reaction that occurs only in acidic solutions

A reaction that can only happen at high temperatures

Explanation

A redox reaction is a type of chemical reaction where one substance is oxidized (loses electrons) and another is reduced (gains electrons), indicating a transfer of electrons.

Question 2

Basic multiple choice Understanding

In a redox reaction, what happens to the substance that is oxidized?

It gains electrons

It loses electrons

Correct

It remains unchanged

It becomes a base

Explanation

The substance that is oxidized in a redox reaction loses electrons, changing its oxidation state.

Question 3

Basic multiple choice Understanding

What is the role of the reducing agent in a redox reaction?

It gains electrons

It loses electrons

Correct

It catalyzes the reaction

It remains neutral

Explanation

The reducing agent is the substance that donates electrons in a redox reaction, thus causing the reduction of another substance.

Question 4

Basic multiple choice Remembering

What occurs during the reduction portion of a redox reaction?

A substance is oxidized

A substance gains electrons

Correct

A substance loses protons

A substance is neutralized

Explanation

During the reduction process, a substance gains electrons, which decreases its oxidation state.

Question 5

Basic multiple choice Understanding

Which of the following statements is true about redox reactions?

Only one substance can be oxidized at a time

They must involve an oxidation and a reduction simultaneously

Correct

They occur exclusively in metals

They do not involve energy changes

Explanation

Redox reactions always involve both oxidation and reduction processes occurring simultaneously, which are complementary to each other.

Question 6

Complex multiple choice Understanding

In a redox reaction where substance A is oxidized and substance B is reduced, what can be inferred about the change in oxidation states of these substances? Choose the correct statement.

Substance A's oxidation state increases, while substance B's oxidation state decreases.

Correct

Substance A's oxidation state decreases, while substance B's oxidation state increases.

Both substances A and B have their oxidation states remain the same.

Substance A gains electrons while substance B loses electrons.

Explanation

The correct answer is that Substance A's oxidation state increases while Substance B's oxidation state decreases, which is characteristic of redox reactions where oxidation involves losing electrons and reduction involves gaining electrons. The other options describe incorrect relationships between oxidation states.

Question 7

Complex multiple choice Understanding

During a laboratory experiment, an unknown metal reacts with oxygen in a redox reaction, forming an oxide. If the oxide has a lower oxidation state than the original metal, what can be concluded about the metal's behavior in the reaction? Select the most accurate conclusion.

The metal was oxidized and lost electrons.

Correct

The metal was reduced and gained electrons.

The metal underwent no change in its oxidation state.

The metal only acted as a catalyst in the reaction.

Explanation

The correct answer indicates that the metal was oxidized and lost electrons, leading to the formation of an oxide with a lower oxidation state. The other options misinterpret the role of the metal in the reaction, which does involve a change in oxidation state.

Question 8

Case based multiple choice Understanding

[Case Scenario] A high school chemistry class conducts an experiment to observe a simple redox reaction between zinc metal and copper sulfate solution. The students set up the equipment and measure the initial concentrations of their reactants. After some time, they observe that the color of the copper sulfate solution changes from blue to colorless, and metallic copper precipitates at the bottom of the beaker. The teacher asks them to analyze the results and determine what occurred at the molecular level during this reaction. Question: Based on the observations made during the experiment, which statement correctly describes the redox processes that occurred?

Zinc was oxidized and copper ions were reduced.

Correct

Copper ions were oxidized and zinc was reduced.

Both zinc and copper ions were oxidized in the reaction.

No redox process occurred as both reactants remained unchanged.

Explanation

In this experiment, zinc metal reacts with copper sulfate solution. Zinc displaces copper, leading to the oxidation of zinc and reduction of copper ions, resulting in a color change and deposition of metallic copper.

Question 9

Case based multiple choice Understanding

[Case Scenario] In a laboratory, students explore a redox reaction by combining potassium dichromate (K2Cr2O7) with a reducing agent, sodium bisulfite (NaHSO3), in an acidified solution. During the experiment, students notice the orange color of the potassium dichromate slowly fades to green. They are tasked with understanding what happens to the oxidation states of chromium in this process. Question: What can students conclude about the change in oxidation states during this redox reaction?

The oxidation state of chromium decreases from +6 to +3.

Correct

The oxidation state of chromium increases from +3 to +6.

The oxidation state of chromium remains unchanged at +6.

Sodium bisulfite is oxidized and chromium is reduced to +3.

Explanation

The observation of color change from orange to green indicates that the chromium in the potassium dichromate is being reduced, thus its oxidation state decreases from +6 to +3 as it undergoes this redox reaction.

Question 10

Case based multiple choice Understanding

[Case Scenario] A chemistry student conducts an electrochemical experiment using a galvanic cell composed of a zinc electrode and a copper electrode. The student notes the flow of electrons from the zinc electrode to the copper electrode, which is associated with a voltage reading on the voltmeter attached to the cell. The student is required to analyze the overall cell reactions and identify the species being reduced and oxidized. Question: Based on the operation of the galvanic cell, which of the following statements accurately describes the redox reactions occurring?

Zinc is oxidized and copper ions are reduced at their respective electrodes.

Correct

Copper is oxidized and zinc ions are reduced at their respective electrodes.

Both zinc and copper undergo oxidation in this cell.

No oxidation or reduction occurs in a galvanic cell as it is a closed system.

Explanation

In the galvanic cell, zinc serves as the anode where it is oxidized, while copper ions in solution serve as the cathode where they gain electrons and are reduced. This creates a flow of electrons generating electricity.