1. What’s the MATTER, part II

2. Types of Matter Pure Substance- Matter with a fixed composition
It has distinct properties
Examples = elements
compounds

3. Mixtures- Most matter is a mixture
The composition is not fixed (changes from sample to sample)
Two Types –
Homogeneous
Heterogeneous

4. Homogeneous Mixtures Composition is uniform throughout
True Solution- (typically transparent)
Particle size = 0.01 – 1 nm
Doesn’t settle out upon standing
Can’t be separated by filtering
Doesn’t scatter light
Example = distilled water

5. Heterogeneous Mixtures
Colloid- (typically translucent /opaque)
Particle size = 1 – 1000 nm
Doesn’t settle out upon standing
Can’t be separated by filtering
Scatters light (Tyndall Effect)
Examples = milk, gelatin, smoke

6. Heterogeneous Mixtures
Suspension
The sample varies in composition, properties and appearance
No Tyndall Effect
Particle size is greater than 1000 nm
Particles settle out upon standing
Can be separated by filtration
Might scatter light
Examples = soil, trail mix, pond water

7. Physical vs. Chemical Properties
Every substance has a unique set of properties (characteristics that identify that substance)
Physical Properties-
Properties that can be measured without changing the identity and composition of the substance

8. Physical Property Examples-
Color
Odor
Density
Melting Point
Boiling Point
Hardness
Solubility

9. Physical Change
A change in matter from one form to another without changing its chemical properties (most can be reversed)
Examples =
Mixing
Dissolving
Compressing
Evaporating
Cutting
Change in State

10. Chemical Properties
Properties that describe the way a substance may change to form other substances
Only observed when a chemical reaction takes place

11. Chemical Property Examples
Heating to combustion
Reactivity with water or acid
Flammability
Corrosion
Decomposition

12. Law of Conservation of Mass
In a physical change or a chemical reaction, mass is neither created or destroyed
(Antoine Lavoisier)

13. Signs of a Chemical Reaction Chemists Get Practice Trying Labs
Color
Gas / Bubbles
Precipitate
Temperature
Endothermic = cold
Exothermic = hot
Light