Question

Explain the differences between a primary galvanic cell - one that is not rechargeable- and a storage cell (e.g., the lead storage battery), which is rechargeable.

Short answer

Primary cells are non-rechargeable, whereas storage cells can be recharged for multiple uses.

Step-by-step solution

Understanding Primary Galvanic Cells

Primary galvanic cells are electrochemical cells that convert chemical energy into electrical energy through a spontaneous redox reaction. They are designed for one-time use and can't be recharged. These cells typically have a finite amount of reactants, and once these are exhausted, the cell cannot produce electricity anymore. Examples include alkaline batteries and zinc-carbon batteries.

Components of Primary Galvanic Cells

Primary cells typically consist of an anode, cathode, and an electrolyte. The anode is where oxidation occurs, and the cathode is where reduction happens. The electrolyte facilitates the flow of ions to balance out the charge as the chemical reaction proceeds. Once the reactants are used up, the cell becomes useless.

Introduction to Storage Cells

Storage cells, also known as secondary cells or rechargeable batteries, can be recharged after their energy has been used up. They convert electrical energy back into chemical energy through non-spontaneous redox reactions when connected to a power source. Lead storage batteries, commonly used in cars, are the classic example of this type of battery.

Components of Storage Cells

Similar to primary cells, storage cells have an anode, cathode, and electrolyte. However, the materials used are chosen to withstand multiple cycles of charging and discharging. For instance, in lead storage batteries, sulfuric acid acts as the electrolyte, and the reactions at the electrodes are reversible.

Comparing Energy Cycles

In primary cells, once the reactants are completely transformed into products during the discharge, the process is irreversible. In storage cells, the discharge process can be reversed during charging, allowing the reactants to form again from the products, making them reusable.

Applications and Utility

Primary cells are commonly used in devices where long shelf life and low discharge current are important, such as remote controls and flashlights. Storage cells are used in high-drain devices and vehicles where periodic recharging is feasible and necessary, providing cost-effectiveness over multiple uses.

Key concepts

Primary Cell

Primary cells are a fundamental type of electrochemical cell that convert chemical energy into electrical energy through spontaneous redox reactions. They are designed only for one-time use, and once the chemical reactants inside are consumed, these cells can't be recharged. Primary cells are often found in household items where replacing the battery is simple and convenient. Examples include:

• Alkaline batteries found in remote controls
• Zinc-carbon batteries used in flashlights

The core components of a primary cell include the anode, cathode, and an electrolyte, each playing a crucial role in the cell's operation.

Storage Cell

Storage cells, also known as secondary cells or rechargeable batteries, differ from primary cells because they can be recharged and used multiple times. This is achieved by reversing the chemical reaction. When you recharge a storage cell, electrical energy is converted back into chemical energy. A typical example is the lead storage battery, widely used in automobiles. In these cells:

• The anode, cathode, and electrolyte are carefully chosen to withstand repeated charging cycles.
• Sulfuric acid serves as the electrolyte, which participates in reversible chemical reactions.

Storage cells are indispensable in modern technology, providing power to portable devices and electric vehicles.

Electrochemical Cell

Electrochemical cells, a broad category, encompass both primary and storage cells. These cells operate on the fundamental principle of converting chemical energy into electrical energy (or vice versa in the case of rechargeables). In every electrochemical cell, two electrodes, the anode and cathode, are immersed in an electrolyte. The main processes involved include:

• Oxidation at the anode
• Reduction at the cathode

Electrochemical cells are integral to many technological applications, from powering small devices to large industrial applications.

Anode and Cathode

The anode and cathode are essential components of any electrochemical cell. Understanding their roles is vital to grasping how these cells work:

• The **anode** is where oxidation occurs, meaning it loses electrons.
• The **cathode** is the site of reduction, gaining electrons.

In a galvanic cell, the flow of electrons from the anode to the cathode through an external circuit is what generates electrical energy. The electrolyte in the cell helps to maintain charge balance by allowing ions to move between the electrodes.

Rechargeable Battery

Rechargeable batteries have revolutionized the way we use electronic devices. Unlike primary cells, they can be recharged and reused, offering both economic and environmental benefits. These batteries work by reversing the discharge chemical reactions through an applied electric current. Key points about rechargeable batteries include:

• They are more cost-effective over time than disposable batteries because they can be recharged many times.
• Common types include lithium-ion and nickel-cadmium batteries, which power laptops, smartphones, and electric cars.

Inventive design and material choice allow rechargeable batteries to hold charge efficiently and last through many cycles of use.