Chemistry: Study of Matter and Its Changes - Matter and Change

1. Ch. 1 – Matter and Change I. Chemistry As a Physical Science

2. Chemistry • Chemistry • the study of the composition, structure, and properties of matter and the changes that matter undergoes • Chemical • any substance that has a definite composition or is used or produced in a chemical process

3. 6 Branches of Chemistry organic chemistry- the study of most carbon-containing chemicals • inorganic chemistry- the study of nonorganic substances

4. 6 Branches of Chemistry • biochemistry- the study of substances and processes occurring in living things • analytical chemistry- the identification of the components and composition of materials

5. 6 Branches of Chemistry • physical chemistry- the study of the properties and changes of matter and their relation to energy

6. 6 Branches of Chemistry • Theoretical chemistry- the use of mathematics and computers to understand the principles behind observed chemical behavior and to design and predict new compounds

7. Chemistry vs. Technology • Basic research- the pursuit of chemical knowledge for its own sake • Applied research- research that is directed toward a practical goal or application

8. Chemistry vs. Technology • Basic research can lead directly to an application, but an application can’t exist before research is done to explain how it works. → need a problem first

9. Chemistry vs. Technology • Chemistry differs from technology… • i.e. Aspirin • Determining the structure of aspirin is chemistry • Using aspirin to relieve pain and reduce fever is technology

10. Ch. 1 – Matter and Change II. Matter and Its Properties

11. MIXTURE PURE SUBSTANCE yes no yes no Is the composition uniform? Can it be chemically decomposed? Colloids Suspensions Matter Flowchart MATTER yes no Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element

12. Pure Substances • Every sample has exactly the same characteristic properties • Every sample has exactly the same composition

13. Pure Substances • Element • composed of identical atoms • EX: copper wire, aluminum foil

14. Pure Substances • Compound • composed of 2 or more elements in a fixed ratio • properties differ from those of individual elements • EX: table salt (NaCl)

15. Pure Substances • For example… Two different compounds, each has a definite composition.

16. Matter Flowchart • Examples: • graphite • pepper • sugar (sucrose) • paint • soda element hetero. mixture compound hetero. mixture solution

17. Mixtures • Variable combination of 2 or more pure substances. Heterogeneous Homogeneous

18. Mixtures • Solution • homogeneous • very small particles • particles don’t settle • EX: rubbing alcohol

19. Mixtures • Suspension • heterogeneous • large particles • particles settle • EX: fresh-squeezed lemonade

20. Mixtures • Examples: • mayonnaise • muddy water • fog • saltwater • Italian salad dressing colloid suspension colloid solution suspension

21. Extensive vs. Intensive • Extensive Property • depends on the amount of matter present • Intensive Property • depends on the identity of substance, not the amount C. Johannesson

22. Extensive vs. Intensive • Examples: • boiling point • volume • mass • density • conductivity intensive extensive extensive intensive intensive C. Johannesson

23. Physical vs. Chemical • Physical Property • can be observed without changing the identity of the substance • Chemical Property • describes the ability of a substance to undergo changes in identity C. Johannesson

24. Physical vs. Chemical • Examples: • melting point • flammable • density • magnetic • tarnishes in air physical chemical physical physical chemical C. Johannesson

25. Physical vs. Chemical • Physical Change • changes the form of a substance without changing its identity • properties remain the same • Chemical Change • changes the identity of a substance • products have different properties C. Johannesson

26. Physical vs. Chemical • Signs of a Chemical Change • change in color or odor • formation of a gas • formation of a precipitate (solid) • change in light or heat C. Johannesson

27. Physical vs. Chemical • Examples: • rusting iron • dissolving in water • burning a log • melting ice • grinding spices chemical physical chemical physical physical C. Johannesson

28. Four States of Matter • Solids • particles vibrate but can’t move around • fixed shape • fixed volume C. Johannesson

29. Four States of Matter • Liquids • particles can move around but are still close together • variable shape • fixed volume C. Johannesson

30. Four States of Matter • Gases • particles can separate and move throughout container • variable shape • variable volume C. Johannesson

31. Four States of Matter • Plasma • particles collide with enough energy to break into charged particles (+/-) • gas-like, variableshape & volume • stars, fluorescentlight bulbs, CRTs C. Johannesson

32. Ch. 1 – Matter and Change III. Elements

33. Modern Periodic Table Period- horizontzal row

34. Modern Periodic Table Group or Family - Vertical column

35. Metals, Nonmetals, Metalloids

36. Metals • solids at room temperature, have a grayish color and shiny surface and conduct electricity • largest region • excellent conductor of heat • lustrous • ductile • malleable

37. Nonmetals • second largest region on table • vary in properties a bit • poor conductor • gases or brittle solids at room temp.

38. Metalloids • an element having properties of metals as well as nonmetals • some have conductive properties • some have luster • some brittle • solid at room temp. • semiconductors