1. UNIT 2 MATTER

2. CLASSIFICATION OF MATTER Matter Pure SubstanceMixture ElementCompoundHomogeneousHeterogeneous Solutions

3. Matter The “stuff” of which the universe is composed It has a mass and takes up space Composed of tiny particles called atoms.

4. Pure Substance Always have the same composition and proportion through out Always have the same physical and chemical properties Are either compounds or elements

5. Elements Pure substances that contain only one type of atom. For example: pure aluminum contains only aluminum atoms

6. Examples of elements Copper Gold Hydrogen Oxygen Silver Carbon Periodic table of elements = ~ 100 elements

7. Classification of elements: metals Located to the left of zig-zag line Conduct heat and electricity Have luster Malleable, ductile High density High melting point Corrosive

8. Classification of elements: nonmetals Located to the right of zig-zag line Do not conduct heat or electricity Dull appearance Brittle solid or a gas Low density Low melting point

9. Compounds Pure substances made by bonding atoms together in specific ways Contain two or more different types of atoms bound in a particular pattern. A specific compound consists of the same particles throughout. For example: dry ice contains the CO 2 molecule. A molecule is made up of atoms that are “stuck” together. Properties of a compound are very different from those of the elements it contains.

10. Examples of compounds Water  H 2 O Hydrogen Peroxide  H 2 O 2 Carbon Monoxide  CO Carbon Dioxide  CO 2 Sodium Chloride  NaCl

11. Mixtures Matter that is impure and has a variable composition. A collection of compounds and/or elements that are present in different amounts. Two types: homogeneous and heterogeneous

12. Heterogeneous Mixture A mixture with regions that have different properties from those of other regions. Doesn’t appear the same throughout. Easily separated.

13. Homogeneous Mixture A mixture that appears the same throughout. Some are called solutions (one substance dissolved in another) It does not vary in composition from one region of the solution to another. Can be separated but a little more work needed. A melted mixture of metals is an alloy. Brass = copper & nickel Bronze = tin & aluminum Pewter = lead & copper Steel = mostly iron with carbon to strengthen

14. Separation of Mixtures Distillation- Boiling to separate the components of a liquid mixture Vaporized gases are captured and condensed back to the liquid phase Filtration – a method of separating a solid from a liquid Condensation – a method of separating gases by lowering the temperature Using physical properties – magnetism, size, shape, dissolving, etc.

15. States of Matter Solid – rigid substance with a fixed volume and shape Liquids – fluid with a fixed volume but takes the shape of the container Gases – fluids with no definite shape or volume because they uniformly fill any container.

16. Phase Changes Melting – solid to liquid; absorbs energy Vaporization – liquid to gas; absorbs energy Condensation – gas to liquid; loses energy Freezing – liquid to solid; loses energy Sublimation – solid to gas; skips the liquid stage because it absorbs energy rapidly

17. HEATING CURVE GRAPH MELT VAPORIZE CONDENSE FREEZE

18. Physical & Chemical Properties Physical Property – characteristics that identify a substance Odor, color, volume, mass, phase, density, boiling/melting point Chemical Property – characteristics that describe how a substance can change into a new substance Ability to burn, rust, sensitivity to light

19. Physical & Chemical Changes Physical change – change in appearance or phase but not composition Chemical Change – Change in composition of a substance into a new substance aka reactions