1. Separation Challenge
How would you separate the following mixtures?
| Mixture | Method | Principle |
|---|---|---|
| Salt and Water | Evaporation | Water evaporates, salt is left behind. |
| Sand and Water | Filtration | Sand is insoluble and stays on filter paper. |
| Iron filings and Sand | Magnetic Separation | Iron is magnetic, sand is not. |
| Oil and Water | Separating Funnel | Oil is less dense and floats on water. |
2. Identify the Mistake
Student Statement: “I made a compound by mixing salt and sugar in a bowl.” Correction: Salt and sugar mixed in a bowl is a Mixture, not a compound.
- Reason 1: No chemical reaction took place (no heat/light/new substance).
- Reason 2: You can still separate them (though difficult, technically possible by solubility differences in alcohol).
- Reason 3: They retain their individual tastes.
3. Diagrams
Draw the particle arrangement for:
- Pure Element (Helium gas): Single atoms far apart.
- Pure Compound (CO2 gas): Molecules (1 Carbon + 2 Oxygen) far apart.
- Mixture (Air): A mix of single atoms (Argon), diatomic molecules (), and compound molecules () floating together.