Various varieties of changes continuously occur in the environment. Some are natural, whereas human activities cause others to meet their needs. These changes can be of two types: physical and chemical change. 

Any chemical change entails one or multiple reactions that result in the formation of a new type of substance. Let us understand more about chemical changes.

Chemical Changes

Some examples of chemical changes are:

1. Raw grains are inedible; however, when cooked, they exchange chemically and turn out to be edible.
2. Many beneficial metals, such as iron, aluminium, and copper, are extracted from their mixed states via a variety of chemical processes.
3. The burning of gasoline is a huge chemical change because it generates a large quantity of warm energy, which is used for home and industrial purposes.
4. Quite a number of life techniques that show up in vegetation and animals are all chemical adjustments that assist to sustain life.

From above, a chemical change is a type of transformation of one material into another, ensuing in new components with different properties and one or more new substances. These changes totally transform a substance; in most cases, we cannot restore the substance to its older form. That means chemical changes are irreversible. 

When a substance undergoes a chemical reaction and divides into multiple other substances, the process is known as chemical decomposition. On the other hand, when two different substances undergo a chemical reaction to combine into a new substance, the process is called chemical synthesis. A chemical reaction can lead to the production of heat and there are also certain chemical reactions that require an external heat source for the reaction to take place. 

Some more examples of chemical changes include:

• Combustion of carbon
• Burning of sulphur 
• Burning of wax 
• Curdling of milk
• Digestion of meals

Rusting

When the molecules of one or perhaps more compounds are reorganised, a chemical reaction occurs, resulting in one or even more new compounds. Rusting is an example of a chemical reaction. When iron is subjected to air, it develops a reddish-brown material called rust, and the process is known as rusting. Rusting is accelerated by the presence of moist air as well as seawater. We can use the following equation to illustrate rusting:

Iron (Fe) + Oxygen (O2, from the air) + Water (H2O) → Rust (Iron oxide, Fe2O3)

Rusting Prevention:

The process of preventing iron objects from being exposed to oxygen, water, or both, is known as the prevention of rust.

Mentioned below are a few ways to prevent rusting:

• Applying a layer of paint or lubricant is one of the most common ways to do it.
• Adding a metal coating to iron, such as chromium or zinc.
• Galvanization is the process of putting a coating of zinc on iron.
• The atmosphere’s ozone layer shields humans from the dangerous ultraviolet (UV) rays. Natural chemical processes involving UV light produce ozone.

Difference Between Physical and Chemical Changes

The difference between the physical and chemical changes are as follows:

Conclusion

Chemical changes are changes in the molecular structure or chemical composition of a substance when they react with each other in the presence or absence of any external catalytic sources. 

Chemical changes are a form of irreversible reaction because there is a change in the molecular structure of the components participating in the reaction during the process. A chemical change is often accompanied by changes in heat and energy. 

There are various chemical changes in our daily life, such as rusting, digestion, baking, etc. This article explains the reasons for some of them.