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Chemistry Basics: Safety, Experiments, and Theories

Explore the world of chemistry with an introduction to lab safety, scientific methods, theories, and historical perspectives. Learn about chemical exposure, the functions of science, types of data, and the evolution of chemistry from alchemy to modern science. Discover different branches of chemistry and potential career paths in the field. Gain insights into manipulating numerical data through graphs for analysis and interpretation.

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Chemistry Basics: Safety, Experiments, and Theories

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

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

  17. a 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

  18. 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

  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 Theory of Gravity, 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 10–9 or 4.3 E –9 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 0.57

  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…

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