Unit 1 Introduction to Chemistry

1. Outline Unit 1Introduction to Chemistry Internet web site: www.unit5.org/chemistry PowerPoint Presentation by Mr. John Bergmann

2. Safety

3. Basic Safety Rules #1 Rule: Use common sense. Others: No horseplay. No unauthorized experiments. Handle chemicals/glassware with respect.

4. Safety Features of the Lab safety shower fire blanket fire extinguisher eye wash fume hood circuit breaker switch

5. Material Safety Data Sheet (MSDS) gives information about a chemical -- -- lists “Dos” and “Don’ts;” emergency procedures

6. e.g., e.g., acuteexposurechronicexposure damage occurs after repeated exposure Chemical Exposure reaction to drugs or medication smoking, asbestos a one-time exposure causes damage

7. LD50 There are various ways an LD50 can be expressed. For example, acetone has the following LD50s: the lethal dosage for 50% of the animals on which the chemical is tested ORL-RAT LD50: 5,800 mg/kg IHL-RAT LD50: 50,100 mg/m3-h SKN-RBT LD50: 20 g/kg

8. Example Chemical A: LD50 = 3.2 mg/kg Chemical B: LD50 = 48 mg/kg Which is more toxic? Chemical A is more toxic because less of it proves fatal to half of a given population.

9. Science

10. the search for knowledge; facts using knowledge in a practical way The Functions of Science e.g., aluminum pure science applied science strong lightweight good conductor

11. Science attempts to establish cause-effect relationships. 

12. risk-benefit analysis weigh pros and cons before deciding Because there are many considerations for each case, “50/50 thinking” rarely applies.

13. How does scientific knowledge advance? 1. curiosity 2. good observations 3. determination 4. persistence

14. The Scientific Method

15. an educated testable prediction Make ahypothesis: Parts of the Scientific Method Repeatedlyexperimentto test hypothesis. procedure: order of events in experiment Identify an unknown. (i.e., a recipe) variable: any factor that could influence the result

16. A ScientificExperiment Experiments must be controlled: they must have two set-ups that differ by only one variable conclusion: must be based on the data

17. ** Key: Be a good observer. observation inference uses the five senses involves a judgment or assumption

18. Types of Data Observations are also called data. qualitative data quantitative data -- -- descriptions measurements e.g., e.g., clear liquid 55 L or 83oC

19. theory: -- -- e.g., law: states what happens -- does not change never violated -- Scientific Law vs. Scientific Theory -- e.g., law of gravity, laws of conservation tries to explain why or how something happens based on current evidence Atomic Theory

20. Phlogiston Theory of Burning 1. Flammable materials contain phlogiston. 2. During burning, phlogiston is released into the air. 3. Burning stops when… …object is out of phlogiston, or …the surrounding air contains too much phlogiston. (superceded by combustion theory of burning)

21. Chemistry

22. ~ D ~ D ___ ___ early practical chemistry: household goods, weapons, soap, wine, basic medicine The Beginning The Greeks believed there were four elements. D earth wind fire water

23. . . . . . . . . . . . . . . . (~500 – 1300 C.E.) the quest for the Philosopher’s Stone Alchemy (the elixir, the Sorcerer’s Stone) Allegedly, this substance would turn cheap metals into gold. Alchemical symbols for substances… GOLD SILVER COPPER IRON SAND

24. Philosopher’s Stone  COPPER GOLD changing one substance into another transmutation: we cannot transmute elements into different elements. In ordinary chemical reactions…

25. Alchemy was practiced in many regions of the world, including China and the Middle East. Alchemy arrived in western Europe around the year 500 C.E. Modern chemistry evolved from alchemy.

26. Contributions of alchemists: • experimental techniques • new glassware • information about elements • developed several alloys

27. What is Chemistry? the study of matter and its changes

28. Areas of Chemistry biochemistry organic the study of carbon- containing compounds the chemistry of living things physical inorganic measuring physical properties of substances studies everything except carbon e.g., compounds containing metals e.g., the melting point of gold

29. Careers in Chemistry • research (new products) • production (quality control) • development (manufacturing) • chemical sales • software engineering • teaching

30. The skills you will develop by an earnest study of chemistry will help you in any career field.

31. The Scope of Chemistry bulk chemical manufacturing pharmaceuticals acids, bases, fertilizers **sulfuric acid (H2SO4) = #1 chemical petroleum products fuels, oils, greases, asphalt 1 in 10,000 new products gets FDA approval synthetic fibers , spandex nylon, polyester, rayon

32. All fields of endeavor are affected by chemistry.

33. Government Regulation of Chemicals The government regulates chemicals to protect the… worker OSHA environment FDA USDA FAA CPSC EPA consumer

34. Manipulating Numerical Data

35. Graphs

36. # of students Bar Graph shows how many of something are in each category

37. Percentage of Weekly Income Pie Graph shows how a whole is broken into parts

38. Stock Price over Time Line Graph shows continuous change In chemistry… you will always use a line graph.

39. Elements of a “good” line graph 2. axes labeled, with units 1. title 3. neat 4. use the available space

40. Essential Math of Chemistry

41. Form: (# from 1 to 9.999) x 10exponent 800 = 8 x 10 x 10 = 8 x 102 2531 = 2.531 x 10 x 10 x 10 = 2.531 x 103 0.0014 = 1.4 101010 = 1.4 x 10–3 Scientific Notation (i.e., to maintain the correct number of significant figures) -- used to express very large or very small numbers, and/or to indicate precision

42. Put in standard form. 1.87 x 10–5 = 0.0000187 3.7 x 108 = 370,000,000 7.88 x 101 = 78.8 2.164 x 10–2 = 0.02164 Change to scientific notation. 12,340 = 1.234 x 104 0.369 = 3.69 x 10–1 0.008 = 8 x 10–3 1,000,000,000 = 1 x 109 6.02 x 1023 = 602,000,000,000,000,000,000,000

43. EE EXP Using the Exponent Key

44. 6 6 6 6 6 1 1 0 0 0 0 0 0 0 x x y x EE EE EE y x 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 . . . . . How to type out 6.02 x 1023: How to type out 6.02 x 1023: The EE or EXP or E key means “times 10 to the…” not… WRONG! WRONG! or… and not… TOO MUCH WORK.

45. Also, know when to hit your (–) sign. (before the number, after the number, or either one)

46. Type this calculation in like this: 1.2 x 105 2.8 x 1019 1 2 Calculator gives… 4.2857143 –15 9 1 8 2 5 or… 4.2857143 E–15 EE EE This is NOT written… 4.3–15 . . = 4.3 x 10–15 or 4.3 E –15 But instead is written…

47. (5.76 x 10–16) (9.86 x 10–4) = –6.5 x 10–19 7.5 x 10–6 (–8.7 x 10–14) = 5.35 x 103 or 5350 4.35 x 106 (1.23 x 10–3) = 5.84 x 10–13 (8.8 x 1011) x (3.3 x 1011) = 2.9 x 1023

48. Essential Mathof Chemistry

49. 5.2 kg (2.9 m) 4.8 kg (23 s) kg.m = = (18 s)(1.3 s) (18 s)(37 s) s2 kg s Units must be carried into the answer, unless they cancel. 0.64 0.17

50. x + y = z Solve for x. x and y are connected by addition. Separate them using subtraction. In general, use opposing functions to separate things. x + y = z – y – y The +y and –y cancel on the left, x = z – y leaving us with…