1. Physical Science Ms. Pollock 2008-2009
Composition of Matter
Physical Science
Ms. Pollock

2. Pure Substances Every material has its own properties.
Properties can be used to identify a material.
Pure substance – type of matter with fixed composition
Element or compound
Helium, aluminum, water, salt

4. Elements All atoms in substance with same identity
About 92 naturally occurring
Over 20 lab-created
Organized in periodic table

6. Compounds
Substance in which two or more atoms are combined in a fixed proportion
Cannot be separated by physical means – must be chemical
Look different from component elements

8. Mixtures
Material made of two or more substances that can easily be separated by physical means
Homogeneous – different materials not easily distinguished
Heterogeneous – different materials easily distinguished

9. Heterogeneous Mixtures
Different materials easily identified
Granite, concrete, dry soup mix
Most everyday substances

10. Homogeneous Mixtures
Two or more gaseous, liquid, or solid substances blended evenly throughout
Vinegar, soft drink (without visible ice)

11. Colloids
Type of mixture with particles that are larger than those in solutions but not heavy enough to settle out
Gelatin, paint, water
Distinguished by Tyndall effect – light scattered by colloids

13. Suspensions
Heterogeneous mixture containing a liquid in which visible particles settle
Muddy pond water, river delta