Chemistry

Study of matter, its properties, and the changes it undergoes.

Basic Concepts

Changes in Matter

How Matter Transforms

Matter can change in many ways. These changes are divided into two main types: physical and chemical.

Physical Changes

A physical change alters how something looks or feels but doesn't change what it is. Examples include:

  • Tearing paper
  • Melting ice
  • Dissolving sugar in water

After a physical change, the substance stays the same at the molecular level.

Chemical Changes

A chemical change creates something new. The original substance becomes a different material with new properties. Signs of chemical change include:

  • Color change
  • Gas formation (bubbles)
  • Temperature change
  • Formation of a solid (precipitate)

Baking a cake, rusting iron, and burning wood are all chemical changes.

Why Do These Changes Matter?

Understanding these changes helps us cook, clean, create new materials, and even understand how our bodies work!

Examples

  • Melting butter is a physical change; frying an egg is a chemical change.

  • Rust forming on a bike is a chemical change; cutting vegetables is a physical change.

In a Nutshell

Physical changes affect appearance but not identity, while chemical changes create something new.