If you put a piece of iron in an aqueous solution of blue \(\mathrm{Cu}^{2+}\) ions, the spontaneous redox reaction \(\mathrm{Fe}+\mathrm{Cu}^{2+} \rightarrow \mathrm{Fe}^{2+}+\mathrm{Cu}\) will occur. An aqueous solution of \(\mathrm{Fe}^{2+}\) ions is red-brown. (a) What is oxidized? (b) What is reduced? (c) What is the oxidizing agent? (d) What is the reducing agent? (e) What will happen to the piece of iron over time? (f) Do the electrons move from the oxidizing agent to the reducing agent or from the reducing agent to the oxidizing agent? (g) How could you use this reaction to make a battery? (Explain and show your battery in a diagram, using a nail and a penny as your source of iron and copper, respectively.)

Step by step solution

01

(a) What is oxidized?

In a redox reaction, the species that loses electrons is said to be oxidized. In this reaction, iron (Fe) loses electrons to form Fe2+: \[\mathrm{Fe} \rightarrow \mathrm{Fe}^{2+} + 2e^{-}\] Thus, iron (Fe) is the species that is oxidized.

02

(b) What is reduced?

In a redox reaction, the species that gains electrons is said to be reduced. In this reaction, Cu2+ gains electrons to form Cu: \[\mathrm{Cu}^{2+} + 2e^{-} \rightarrow \mathrm{Cu}\] Thus, Cu2+ is the species that is reduced.

03

(c) What is the oxidizing agent?

The oxidizing agent is the species that causes the oxidation of another species by taking its electrons. In this reaction, Cu2+ is causing the oxidation of Fe by taking its electrons. Therefore, Cu2+ is the oxidizing agent.

04

(d) What is the reducing agent?

The reducing agent is the species that causes the reduction of another species by providing its electrons. In this reaction, Fe is causing the reduction of Cu2+ by providing its electrons. Therefore, Fe is the reducing agent.

05

(e) What will happen to the piece of iron over time?

As the piece of iron reacts with Cu2+ ions in the aqueous solution to form Fe2+ ions, the piece of iron will gradually dissolve over time. As this occurs, more Fe2+ ions will be present in the solution, giving it a red-brown color.

06

(f) Do the electrons move from the oxidizing agent to the reducing agent or from the reducing agent to the oxidizing agent?

In a redox reaction, electrons are transferred from the reducing agent to the oxidizing agent. In this case, electrons are transferred from Fe (the reducing agent) to Cu2+ (the oxidizing agent).

07

(g) How could you use this reaction to make a battery?

To create a battery using this redox reaction, you can use a nail (made of iron) as the anode and a penny (made of copper) as the cathode. Connect the nail and penny with a wire, and immerse them in an electrolyte solution containing Cu2+ ions. The redox reaction causes electrons to flow from the nail (Fe) to the penny (Cu) through the wire, generating an electric current. Here's a diagram to illustrate the battery setup: ``` |-----| Wire | | | Fe (nail, anode) ------ Solution containing Cu^2+ ions ------- Cu (penny, cathode) | | |-----| ```

Unlock Step-by-Step Solutions & Ace Your Exams!

• Full Textbook Solutions

  Get detailed explanations and key concepts

• Unlimited Al creation

  Al flashcards, explanations, exams and more...

• Ads-free access

  To over 500 millions flashcards

• Money-back guarantee

  We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Oxidation and Reduction

Understanding oxidation and reduction is crucial in chemistry, especially when studying redox reactions. Oxidation refers to the process where an element loses electrons during a reaction. Reduction, on the other hand, occurs when an element gains electrons. These processes always happen simultaneously in a redox reaction, as electrons must be conserved. A mnemonic to remember this is 'LEO the lion says GER': Lose Electrons Oxidation, Gain Electrons Reduction.

For example, in the reaction between iron and copper ions, iron (Fe) is oxidized as it loses two electrons, forming Fe²⁺, while copper ions (Cu²⁺) are reduced as they acquire two electrons to form elemental copper (Cu).

Oxidizing and Reducing Agents

An oxidizing agent is a substance that promotes oxidation by accepting electrons from another species, thus getting reduced itself. Conversely, a reducing agent causes another substance to be reduced by donating electrons, oxidizing in the process.

• The oxidizing agent in our reaction is Cu²⁺, which gains electrons and is reduced to Cu.
• The reducing agent is iron, which loses electrons, and is thereby oxidized to Fe²⁺.

It's essential to recognize these agents to understand the direction of electron flow and predict the outcome of reactions.

Galvanic Cells

Galvanic cells, also known as voltaic cells, are devices that convert chemical energy into electrical energy through spontaneous redox reactions. They comprise two half-cells, each containing an electrode and an electrolyte where oxidation and reduction occur separately. The two half-cells are connected by a salt bridge, allowing ions to flow, while electrons travel through an external circuit from the anode to the cathode, creating an electric current.

The iron and copper reaction can form the basis of a galvanic cell, with the iron electrode (nail) serving as the anode, where oxidation occurs, and the copper electrode (penny) acting as the cathode, where reduction takes place.

Electron Transfer

Electron transfer is the movement of electrons from one species to another. It is the fundamental process in redox reactions, driving the formation of compounds through oxidation and reduction. During this transfer, the reducing agent donates electrons and is oxidized, while the oxidizing agent accepts electrons and is reduced.

In our specific reaction, electrons move from the iron nail to the copper penny in the external circuit, which leads to the generation of electrical energy. It's the flow of electrons that powers devices connected to the battery.

Chemical Battery Construction

Chemical battery construction involves assembling two electrodes made of different materials, connected by an electrolyte that facilitates ion movement. To construct a battery using the iron and copper redox pair, you’ll need an electrolyte solution containing Cu²⁺ ions, a nail as the iron source (anode), and a penny as the copper source (cathode).

When these components are assembled properly, the iron will undergo oxidation at the anode, and the Cu²⁺ ions in the electrolyte will undergo reduction at the cathode. Electrons from the oxidized iron will flow towards the copper through a wire, completing the circuit and allowing the battery to deliver electric current to an external load.