Five examples of Physical and Chemical changes (chemistry project)

 Introduction 

Everything around us undergoes certain changes. Changes can be either physical or chemical. 

Physical change is a type of change where the physical properties of matter change. A change of state of matter, change in colour, odour, solubility, etc. all are examples of physical change.

A chemical change is a type of change where the chemical properties of matter change. It is commonly called a chemical reaction.

 Five examples of physical and chemical changes in day-to-day life:

1. **Physical Change:

a) Ice Melting**: When ice melts, it undergoes a physical change from a solid state to a liquid state. The chemical composition of the water molecules remains the same; only the arrangement of molecules changes as heat energy is absorbed.

b) Cutting Vegetables**: Chopping vegetables is a physical change because it alters the shape and size of the vegetable pieces without changing their chemical composition. The vegetable remains the same substance; only its physical appearance is modified.

c) Dissolving Sugar in Water**: When you dissolve sugar in water, it undergoes a physical change. The sugar molecules disperse throughout the water, but their chemical composition remains unchanged. It's a reversible process since you can evaporate the water to retrieve the sugar.

d) Crushing a Can: When you crush an aluminum can, it undergoes a physical change as its shape is altered without any change in its chemical composition. The aluminum remains aluminum, but its form is now flattened.

e) Crumpling Paper: Crumpling a piece of paper involves a physical change because it alters the shape and texture of the paper without changing its chemical composition. The paper remains paper, but its appearance is modified.

2. **Chemical Change:

a) Burning of a Natural Gas

This is a clear example of a combustion reaction. Natural gas comprehends methane gas. When methane reacts with oxygen in the atmosphere it produces water and carbon dioxide. Hence, it is an example of chemical change.

b) Burning of Wood: When wood burns, it undergoes a chemical change known as combustion. The heat breaks down the complex organic molecules in wood into simpler compounds such as carbon dioxide, water vapor, and ash, releasing energy in the form of heat and light.

c) Souring of Milk: When milk sours, it undergoes a chemical change due to the action of bacteria on the lactose sugar present in the milk. The bacteria ferment the lactose, producing lactic acid, which causes the milk to curdle and develop a sour taste.

d) Cooking an Egg**: When you cook an egg, chemical changes occur as the proteins in the egg white denature and coagulate, turning from a transparent liquid into a solid white. The heat causes chemical bonds within the proteins to break and reform in a different structure.

e) Rusting of Iron**: When iron is exposed to oxygen and moisture, it undergoes a chemical change known as rusting. Iron oxide forms on the surface of the iron, causing it to corrode. This process alters the chemical composition of the iron.

Conclusion

This project on changes in chemistry has deepened our understanding of how substances transform, both physically and chemically. By exploring factors like temperature and concentration, we've uncovered insights with practical applications in various fields. This research underscores the importance of continued exploration in chemistry and its relevance to real-world challenges.