CHEM 3070

1. CHEM 3070 Fall 2006 Chad Stessman

2. Chapter 1 • Chemistry is a Science- two components • Technological- facts, knowing how to do things.

3. Philosophical- theoretical, why do things happen. • What might happen with an unknown system • Started with ancient Greeks 2500 years ago

4. Chemistry • Chemistry is a branch of science that investigates how matter interacts with other matter. • Roots in alchemy (500-1500 AD) attempts to convert cheaper metals to gold.

5. Scientific Method • Observations- accumulation of knowledge about the natural world • Must be reproducible and observable by others

6. Develop a hypothesis-educated guess, to explain the observation. • Design an experiment to test the hypothesis.

7. Develop a hypothesis-educated guess, to explain the observation. • Design an experiment to test the hypothesis. Baa Baa

8. Develop a hypothesis-educated guess, to explain the observation. • Design an experiment to test the hypothesis. Baa Baa

9. Must be a testable property or idea. • If the test rejects the hypothesis a new hypothesis is developed. • This new hypothesis is then tested • If experiment is verifies the hypothesis then it is repeated.

10. Theories • Eventually after enough verifying a hypothesis becomes a theory • Theory-best explanation of various phenomena as of today. • Always tentative, could be discarded or modified if new evidence is discovered. • Theories can be used to predict behavior.

11. Law • Large amounts of scientific data can be summarized in a brief statement, Law • Universal under the stated conditions.

12. Newton’s Laws of Motion • Objects in motion tend to stay in motion unless an external force is applied to it. • Force equal mass times acceleration F=ma

13. Model • Scientists use simple, maybe common examples to explain complicated systems. • Models have limitations, and at some point diverge from the systems they are models for.

14. Limitations on Science • Limited by the number of variables • Must hold all but one variable constant • With more advanced systems this becomes more and more difficult. • Math, physics, chemistry, biology, social sciences

15. Risks vs. Benefits • Every technology has certain risks, and benefits • Benefits-advantages to certain technology • Risks- hazards that lead to loss or injury

16. Desirability Quotient • A way to determine the desirability of a certain technology • DQ= benefits/risks • Positive number good, negative bad

17. Pasteurized Milk • Benefits-safe, clean and nutritious, a source of calcium • Risks-some people are lactose intolerant • DQ = High benefit/low risk

18. Thalidomide • Drug used in 1958 to reduce morning sickness (benefit) • Found to cause birth defects (risk) • DQ(thalidomide) low benefit/ high risk

19. Other examples • Lead paint • Aspirin • Space program

20. Chemistry’s Central Role • Chemistry is central to most sciences • Biology, agricultural sciences, medicine, communications, geology, etc.

21. Chemistry Research • Broken into two areas • Applied research- trying to find solutions to specific problems. Find new drugs, finding new plastics • Basic Research-investigation for knowledge’s sake.

22. Chemistry-study of matter • Matter-stuff that makes up all things, it has a mass. • Mass- measure of the quantity of matter contained in an object. Greater mass the harder it is to change motion. • Mass is the same anywhere in the universe

23. Weight • Weight differs from Mass • Weight is a measure of force • Weight=mass x acceleration due to gravity

24. Physical vs. Chemical Properties • Physical Property- physical characteristic and behavior. Color, odor, hardness • Chemical Property- how a material interacts with other types of matter

25. Physical vs. Chemical Changes • Physical Change- a change that does not entail a change in the chemical composition. Ex. melting point, boiling point • Chemical change- involves a chemical change in the matter. Ex. burning, rusting

26. States of Matter • Three common states of matter • Solid, liquid and gas

27. Solid • Maintains its ordinary shape and volume regardless of location. • Ex. ice, gold bar, coins

28. Liquid • Occupies a definite volume but assumes the shape of its container. • Ex. water, ethanol, gasoline

29. Gas • Maintains neither shape nor volume. It expands to fill the container it is in. Can be compressed. • Ex. steam, oxygen, air

30. Substance and Mixture • Substance- has a definite or fixed composition that does not vary sample to sample. Ex. pure water, 24-carat gold, 200-proof ethanol • Mixture-composition is variable. Ex. salt water, 14-carat gold, air

31. Elements and compounds • Substances are either elements or compounds • Elements-fundamental substances of which all matter is composed. Ex. gold, oxygen, nitrogen • Compounds-substances made up of two or more elements chemically combined. Ex water, ethanol

32. Elements • Currently 115 substance which can not be broken down into simpler substances by chemical means. • Carbon, oxygen, helium, iron, often refered to by shorthand notation, derived from first to letters of Latin name.

33. Atoms and molecules • Atom- smallest characteristic part of an element • Molecule- a group of atoms bonded together as a unit. Each molecule is the basic component of a compound

34. Measure of Matter • To do scientific work we need accurate measurements of quantities of mass, volume, temperature, time ….. • Since 1960 International System of Units, SI system has been used by scientists.

35. Length-meter (m) Mass- kilogram (kg) Time- second (s) Temperature- Kelvin (K) Amount- mole (mol) Electric current-ampere (A) Luminous intensity- candela (cd) SI system has seven basis units