2. Unit: Introduction to Chemistry
Day 2 - Notes
Unit: Introduction to Chemistry
Classification of Matter

3. The study of matter and the changes it undergoes.
Chemistry:
The study of matter and the changes it undergoes.

4. Some terms you’ve seen before...
Matter: anything that has mass and volume (EVERYTHING!)
Mass: the amount of matter in an object (How much “stuff”)
Energy: Anything that can do work or produce heat.
Weight: The force of gravity acting on an object’s mass.
Mass is dependent on how much matter an object has. Weight is dependent on the attraction between two objects, ex: a 100g mass and the Earth.
Mass is measured by a standard triple beam balance. Where weight is measured by a spring scale.

5. Review: Solids, Liquids, and Gases
Definite shape
Definite volume
Not compressible
High density
Indefinite shape
Less dense than solids
Indefinite volume
Are compressible
Very low density

6. There are two major areas that matter are classified into:
pure substances and mixtures.

7. Pure Substances Have uniform and definite composition
Elements: found on the Periodic Table (approx. 118)
Described by symbols: H, He, etc.
Compounds: formed when elements chemically combine: H2O, CO2, NO2

8. Mixtures Two or more pure substances physically mixed together.
In compounds, the elements are bonded to each other
In mixtures, the substances are blended
No definite composition – cannot assign a fixed ratio (ex: H2O)

9. Two Types of Mixtures:
Heterogeneous mixtures: does not have a uniform composition
Parts of the mixture can be physically seen and “picked out” of the mixture
Examples: Cereal, pizza, salad

10. Homogeneous mixtures: has a uniform composition
Parts of the mixture cannot be “picked out”
Examples: sugar water, milk

11. Ways of Separating Mixtures
Differences in physical properties can be used to separate mixtures.
Filtration - separates a solid from the liquid in a heterogeneous mixture (by size)
Distillation – separates a solution by boiling points
There are other ways as well: magnets, evporation chromotography

19. Complete an exit ticket!
Questions?
Complete an exit ticket!