📚 What is a Pure Substance?
A pure substance is matter that has a fixed chemical composition and distinct properties. This means it's made up of only one type of atom or molecule.
- ⚛️ It consists of only one type of particle.
- 🧪 It has a definite and constant composition.
- 🌡️ It has specific melting and boiling points.
🔬 What is a Compound?
A compound is a substance formed when two or more elements are chemically bonded together in a fixed ratio. This bonding changes the properties of the individual elements.
- 🔗 It is formed by the chemical combination of two or more elements.
- ⚖️ The elements are combined in a fixed ratio.
- 🔥 It has properties different from its constituent elements.
🧪 Pure Substance vs. Compound: Side-by-Side Comparison
| Feature |
Pure Substance |
Compound |
| Definition |
Made up of only one type of atom or molecule. |
Made up of two or more different elements chemically bonded. |
| Composition |
Fixed and definite. |
Fixed ratio of elements. |
| Separation |
Cannot be broken down into simpler substances by physical means. |
Can be broken down into simpler substances by chemical means. |
| Examples |
Gold (Au), Oxygen ($O_2$). |
Water ($H_2O$), Sodium Chloride (NaCl). |
| Melting/Boiling Point |
Sharp and constant. |
Sharp and constant after purification. |
💡 Key Takeaways
- 🧱 Pure substances are the basic building blocks; compounds are structures built from different blocks connected together.
- ⚗️ Elements are the simplest form of pure substance, while compounds are combinations of different elements.
- ⚡ Breaking down compounds requires chemical reactions, whereas pure substances remain as they are unless nuclear reactions are involved.