Question

What are the chemical similarities between the following processes: a. combustion of gasoline in an automobile engine b. metabolism of foods in our bodies c. rusting of iron

Short answer

The chemical similarities between the combustion of gasoline, metabolism of food, and rusting of iron include being redox reactions with oxygen as the oxidizing agent, the release of energy, chemical transformation of reactants into new products, and the generation of byproducts such as carbon dioxide and water.

Step-by-step solution

Identify the process type

Determine that all three processes are redox reactions, involving the transfer of electrons from one substance to another.

Recognize the oxidizing agent

Identify that in each process, oxygen acts as the oxidizing agent that accepts electrons.

Describe energy changes

Note that all three processes release energy, although in different forms: combustion releases thermal energy, metabolism releases energy stored in ATP, and rusting releases energy as the overall potential energy of the system decreases.

Examine chemical change

Understand that all three processes lead to chemical changes where reactants are converted into different products: combustion results in carbon dioxide and water; metabolism produces carbon dioxide, water, and others; rusting forms iron oxides.

Discuss byproducts

Recognize that all processes produce byproducts: combustion leads to emissions like CO2; metabolism generates CO2 and other waste products; rusting yields various forms of iron oxide.

Key concepts

Oxidation-Reduction Process

The term 'oxidation-reduction process', commonly known as a redox reaction, refers to a chemical reaction where the oxidation states of atoms are changed. Oxidation involves the loss of electrons or an increase in oxidation state by a molecule, atom, or ion. In contrast, reduction means the gain of electrons or a decrease in oxidation state. The easiest way to remember this is the mnemonic 'OIL RIG': Oxidation Is Loss, Reduction Is Gain.

Considering the exercise provided, the combustion of gasoline, metabolism of food, and rusting of iron all involve redox reactions. In these processes, electrons are transferred between chemical species, resulting in energy release and the creation of new products. For example, in an automobile engine, the combustion of gasoline involves the oxidation of hydrocarbons, which releases energy to power the vehicle. Similarly, in our bodies, the metabolism of food breaks down nutrients, releasing the energy necessary for life processes.

Oxidizing Agents

An oxidizing agent, or oxidant, plays a pivotal role in the redox reaction by accepting electrons from another substance—thus being reduced itself. The strength of an oxidizing agent is determined by its ability to gain electrons; the stronger the agent, the more easily it gains electrons and oxidizes other substances. This concept is crucial when examining reactions like combustion, metabolism, and rusting, as they all involve a common oxidizing agent: oxygen.

Oxygen's high affinity for electrons makes it an excellent oxidizer. It's involved in the combustion of gasoline, where it accepts electrons from the fuel, in the metabolism of food molecules where it aids in converting biochemical energy into adenosine triphosphate (ATP), and in the corrosion process of iron, leading to rust formation. Oxygen's ubiquitous role highlights why it's considered one of the most common oxidizing agents in chemical reactions.

Chemical Energy Changes

Chemical energy changes are intricately linked to redox reactions. When electrons are transferred during these reactions, energy is either released or absorbed, changing the chemical energy of the involved substances. Whether energy is released in the form of heat, light, or stored in chemical bonds, it is all governed by the principle of energy conservation.

In the combustion of gasoline, a large amount of energy is released as heat, which propels the car. The metabolism of food in our bodies releases energy that is encapsulated in ATP, the energy currency of cells, which can be used for various bodily functions. And iron rusting, while less dramatic, involves a decrease in energy as electrons are lost to oxygen, forming a more stable compound. These diverse processes all reflect the transformation of chemical energy during redox reactions, underscoring the versatility and fundamental nature of these processes in both human-made systems and nature.

• Combustion of gasoline: releases thermal energy.
• Metabolism of foods: releases chemical energy in ATP form.
• Rusting of iron: releases energy due to a decrease in potential energy of the system.