What does “Pure” mean?
In daily life, “Pure Milk” means milk without added water or adulterants. In Science, “Pure Milk” is actually a Mixture (of water, fats, proteins, sugars).
Scientific Definition: A Pure Substance is a form of matter that has only one type of particle.
- It cannot be separated into other kinds of matter by physical processes.
- It has a fixed composition and distinct properties.
Classification
Pure substances are divided into two types:
- Elements: Made of only one type of atom (e.g., Gold, Oxygen).
- Compounds: Made of two or more types of atoms combined chemically in a fixed ratio (e.g., Water, Salt).
Tip
Thought Experiment: If you could zoom into a glass of pure water, you would see billions of identical molecules. If you zoomed into a gold ring, you would see billions of identical Gold () atoms.