The break down of our materials and figure out who falls under the category of “pure substances” and who’s in the “mixture” group.

1. Ice:
– Pure substance. Think of it as frozen water; it’s made up of H2O molecules and nothing else.

2. Iron:
– Pure substance. In its elemental form, iron stands alone as a pure substance.

3. Hydrochloric acid:
– Pure substance. It’s like the chemical superhero in our collection, with a specific composition (HCl).

4. Calcium oxide:
– Pure substance. Meet quicklime – it’s a pure substance with a defined composition (CaO).

5. Mercury:
– Pure substance. In its elemental liquid form, mercury is a pure substance.

Now, let’s turn our attention to the more social materials:

– Milk: – Mixture. It’s a blend of water, fats, proteins, lactose, and various other components. No solo act here.

– Brick: – Mixture. A combination of different minerals and materials, not a pure substance.

– Wood: – Mixture. With cellulose, lignin, water, and a variety of components, wood is more of a mix than a pure substance.

– Air:
– Mixture. It’s like a symphony of gases – nitrogen, oxygen, carbon dioxide – definitely not a solo performer.