1. Chapter 15: Classification of matter

2. Composition of Matter Matter can exist as:
Substance: Type of matter with a fixed composition; can be element or compound; Ex: He, water, salt
Element: Substance made up of atoms that are all alike; cannot be broken down into any other substance
Ex: graphite in pencil point
Compound: Substance in which the atoms of 2 or more elements are chemically combined in a fixed proportion
Ex: water, CO2
Mixture: Matter composed of two or more substances that can be separated by physical means

3. mixtures
Heterogeneous Mixture: Mixture in which different materials remain distinct
Ex: Salad, oil and vinegar dressing
Suspension: A heterogeneous mixture made of a liquid and solid particles that settle
Ex: River deltas, seasoning in salad dressing
Colloids: A heterogeneous mixture with particles that never settle
Ex: milk (water, fats, proteins), fog (liquid suspended in air)
Note: you can identify a colloid by shining a light through it; light beam is invisible as it passes through a solution, but it can be seen as it passes through a colloid; This scattering of light through a colloid is called the Tyndall Effect

4. Mixtures
Homogeneous Mixture: A mixture that remains constantly and uniformly mixed and has particles that are so small that they cannot be seen with a microscope; solution is same thing as a solution Ex: tea, vinegar

5. Properties of matter: PhysicAl
Physical Property: Any characteristic that you can observe without changing the identity of a substance Ex: color, shape, size, density, melting point, boiling point, viscosity, solubility, malleability, conductivity, melting point, boiling point, solubility Distillation: Process of separating substances in a mixture by evaporating a liquid and recondensing its vapor Ex: separate 2 liquids with different boiling points

6. Properties of matter: chemical
Chemical Property: Any characteristic of a material that you can observe that produces one or more new substances,;describe the ability of a substance to change into another substance Ex: flammability and reactivity

7. Physical and chemical changes
PHYSICAL CHANGES IN MATTER
Physical changes only change physical properties of a substance
Does not produce a new substance
Phase changes are physical
Ex: breaking, bending, melting, freezing, tearing, dissolving

8. Physical and chemical changes
CHEMICAL CHANGES IN MATTER
The process by which a substance changes into another substance Does not produce a new substance
Also called chemical reactions
Ex: Burning, rusting, baking soda and vinegar

9. Law of Conservation of Mass: total mass of the reactants = total mass of the products