2. Thank you for wearing your IDs and Keeping all electronics put away. Grab your notebook

3. Chemistry The study of matter

4. Matter Anything with mass that takes up space. Density = Mass/volume(space) Density is a physical property used to identify matter.

5. Classification of matter- This is done using both chemical and physical properties of the substances. Element (Ele) Compound (Cpd) Mixtures (Mix.)

6. Elements Made of only 1 type of atom Homogeneous-uniform throughout 118 currently known to exist Represented by symbols taken from the Latin names Classified into –Metals –Nonmetals –Metalloids

7. Metals True metals Shiny/luster Soft Silver or grey Conducts electricity/heat Malleable/ductile HighTensile strength Very reactive Transitional metals Same characteristics as true metals but to a lesser degree. Two have color- Copper and Gold. Cpds of these ele. are very colorful.

8. Nonmetals Solids, liquid, and gases Those that are solids are very brittle Do not conduct heat/electricity (insulators) Special type of nonmetal are the noble gases –Nonreactive or inert.

9. Metalloids These are located on the staircase Metalloids have characteristics of both metals and nonmetals –Example Silicon is very brittle but will conduct electricity.

10. A property of all elements One characteristic that all elements have in common is that they cannot be decomposed by ordinary chemical means. They can’t be broken down into simpler substances.

11. Compounds Consist of 2 or more different elements chemically bonded together When bonded the elements lose their physical/chemical properties and they form new properties. Infinite number of cpds Composition of these elements within a compound is always constant

12. Compounds Represented by formulas CaCO 3 H 2 O 2 Classified as –Organic- –Inorganic-

13. Organic cpds Organic cpds are hydrocarbons- These cpds come from living or once living things –Wood –Wool –Petroleum –Plastic

14. Inorganic cpds Inorganic cpds do not contain Hydrogen and carbon together in its formula –Salt NaCl –Sand SiO 2 -Water H 2 O

15. Mixtures (Not a pure substance) Homogeneous Uniform throughout Looks like a pure substance All homogeneous mixtures are called solutions –Saline –Air –Alloys Heterogeneous Nonuniform throughout Can see the parts of the mixture Examples –quartz –smog –Italian salad dressing

16. Mixtures Do not have constant compositions Each component of the mixture retains its own identity and keeps their properties Can be separated using physical methods

17. Physical Properties Uses the five senses –Touch, taste, smell, etc The measuring of a physical property does not change the substances identity.

18. Physical properties Extensive properties depend on the amount of substance –Mass,Volume,Shape Intensive properties do not depend on the amount of substance –Color, phase,melting pt, boiling pt, density etc

19. Chemical Properties Describe how the substance behaves or reacts with other substances and in the process will change the identity of the substance. –Does it burn? –Does it oxidize or rust? –Does it react with X? –(Chemical Properties always involve chemical changes.)

20. Physical and Chemical Changes Physical: any change in a physical property that retains the substances identity Chemical: any change in a substance that brings about a change in the substances identity You can tell this if the –color changes –a gas if formed –the temp. changes –or a precipitate (ppt) is created.

21. Recap Physical Properties Describe what a substance is like. Chemical Properties Describe how a substance behaves or reacts. Always accompanied by –Color change, temp. change, gas forming or, ppt.

22. Changes Physical changes involve a change in some aspect of the substance WITHOUT changing what it is Chemical changes always involve a change in what the substance is. Evidence… –Color change –Temp change –Gas forms –Ppt.