Properties of Matter

1. Properties of Matter Mr. Roberts Adapted from material by Ian Guch

2. Homogeneousmaterials • Materials that are completely uniform in composition all the way through. • All parts of the material have an identical composition and appearance.

3. Homogeneous Materials • There are three subclasses within this: • Element: When only one type of atom is present in a material. If it’s on the periodic table, it’s an element. • Compound: A pure substance that contains only one type of molecule. • If something has a chemical formula or chemical name, it’s probably a compound • Homogeneous mixture (also called a “solution”): A mixture in which all the components are so mixed together that they cannot be unmixed

4. Heterogeneous materials • Materials that do not have the same composition throughout. • Frequently appear speckled, spotty, chunky, etc.

5. How to tell these types of materials apart:

6. Chemical And Physical Changes • Question to ask yourself – “Can this be changed back to what I started with?” • If no, then it is probably a chemical change

7. Chemical change: • Any change that causes one material to turn into a different material with a different chemical makeup. • In a chemical change, chemical bonds are broken and reformed in different patterns. • Examples??? • examples of chemical changes, such as burning, rusting, rotting, decomposing, growth, etc.

8. Physical change: • Changes that alter the appearance but not the chemical composition of a material. • Examples??? • phase changes, bending, dissolving, etc.

9. Evidence for each type of change:

10. Definition of chemical and physical properties: • chemical property: any property that explains the capacity of a compound to turn into another compound. These things can’t be tested without (potentially) doing a chemical change. • Examples: flammability, resistance to acids, etc. • physical property: any property that has nothing to do with changing it to a different substance. These properties can be determined without (potentially) doing a chemical change. • Melting/boiling point, color, solubility, density, etc. • All properties are either chemical or physical properties (but not both)