1. Spring, 20111 Fall, 2010 1 GECH119 A Brief History of Chemistry Dr. Ralph C. Gatrone Virginia State University Department of Chemistry and Physics

2. Spring, 20112 Fall, 2010 2 Chapter Objectives  Introduce Origins of Universe  Introduce Origins of Science  Introduce History of Chemistry

3. Spring, 20113 Fall, 2010 3 Origins: Description of Creation  Based upon scientific observation  Incomplete  Imperfect  Unwitnessed  Most accurate account available  Testable  Reproducible  Supportable

4. Spring, 20114 Fall, 2010 4 Observations  Universe is large  Universe is expanding  Universe must have been smaller  Define underlying relationships  Big Bang  Physics allows us to work backwards  This requires measurement and quantification  Underlying relationships can be defined

5. Spring, 20115 Fall, 2010 5 Measurement and Quantification  Agree upon standard units of measurement –International System of Units (SI Units)  Base Units –Mass – kilogram (Kg) –Length – meter (m) –Time – second (s) –Temperature – Kelvin (K)  From these we get the derived units –Volume, density, speed, force, energy

6. Example  As you drive by an intersection, you observe  Two parked cars. One has a mangled front end. The other a mangled back end.  Conclusions you can draw. Spring, 20116

7. Example  But you did not see the accident happening. Spring, 20117

8. 8 Fall, 2010 8 Direct and Indirect Data  Direct data – –First hand observation  Indirect data –Infer event from clues left behind –Development of models

9. Spring, 20119 Fall, 2010 9 The Big Bang  Universe was small and very hot  Matter/Energy were inter converting  Matter – mass and volume  Energy – capacity to do work  Relationship: E = mc 2  Universe began cooling and expanding  More energy then matter, but with cooling  Amount of matter began increasing

10. Spring, 201110 Fall, 2010 10 How can we say this?  The Big Bang Theory  Incorporates present data  Incorporates present observations  Predicts results of future experiments  If new observation agrees with Theory –Basic concept is supported –Progress continues  If new observation does not agree with Theory –Theory must be modified or replaced –Progress continues

11. Spring, 201111 Fall, 2010 11 Big Bang Model  Theory developed from indirect data  Model explains this data  Model predicts future experiments and observations

12. Spring, 201112 Fall, 2010 12 Formation of the Elements  Universe cooled after Big Bang  Electrons attached themselves to H and He  Gravity caused matter to collect in clumps  As clumps increased in size electrons were driven off the atoms – plasma formation  Nuclear fusion began – star formation  H atoms fuse to form He + energy released  Galaxies formed

13. Spring, 201113 Fall, 2010 13 Formation of the Elements  H fuses to become He  As H fuel is used He fuses to form Li or Be  Be + He gave C  As atoms get larger energy is required to continue fusion  Fusion stops at formation of Fe  What happens next?  Depends upon size of the star  Some stars slowly cool and dim  Gravity pulls all material inward  Implosion followed by explosion  Supernova  Heavy elements (masses bigger than Fe) formed by this process  Some are radioactive and form other elements through radioactive decay

14. Spring, 201114 Fall, 2010 14 What is Chemistry?  Chemistry is defined as the study of matter and its properties.  When did we begin doing chemistry?  When did we begin doing science?

15. Spring, 201115 Fall, 2010 15 The Beginning  Prehistory - 2,000,000 to 5000 years ago  Paleolithic  Defined by crude stone tools  Neolithic - 12,000 years ago  Defined by complex stone tools

16. Spring, 201116 Science and Technology   Science – a collection of knowledge   Primarily concerns the universe and its behavior   Study does not require a particular goal or objective beyond just knowing   Technology – application of scientific knowledge

17. Spring, 201117 Fall, 2010 17 Science and Technology  Separate paths  Little trace of science during prehistory  Use of Technology evident  Tool use  Not purely human  Rooted in biology  Observed in nonhumans  Requires thought  Making tools is essential to human existence

18. Spring, 201118 Fall, 2010 18 Technology  Humans  Only species to make tools used to make tools  Human society requires technology advancement for survival

19. Spring, 201119 Fall, 2010 19 Technological Advances  Control of fire  Provided warmth  Enabled migration into cold climates  Provided light  Enabled activity after dark and in dark places  Provided protection  Enabled cooking – aid to digestion  Hardened tools  Enabled social and cultural development

20. Spring, 201120 Fall, 2010 20 Advances  Grasping hand – evolution  Speech – empowered dramatic social changes with cultural consequences  40,000 years ago  Neanderthal extinct  Homo sapiens  Produced specialized tools  Began trade  Produced art  Buried their dead

21. Spring, 201121 Fall, 2010 21 Homo sapiens  Nomadic  Technology related to food gathering and processing  No surplus food  No institutions necessary  Labor was divided by gender  Population growth forced food collectors  To become food producers

22. Spring, 201122 Fall, 2010 22 Food Producers  Mastery of a set of technologies  Science?  Practical knowledge is different from understanding a phenomenon  Absence of records suggests science was not pursued  Possessed extensive knowledge of nature  Keen observers  May have categorized observations

23. Spring, 201123 Fall, 2010 23 Records  Recorded moon observations on bone  (engraved mammoth tusk from Ukraine)  2,000,000  food collectors  little technology  200,000  Same lack of progress by our species  15,000 years ago  Accelerated pace  Why?

24. Spring, 201124 Fall, 2010 24 Pace Increased  Climate change  Extinction of many large animals  Population increase  Formation of large communities for survival  Farming  Animal domestication

25. Spring, 201125 Fall, 2010 25 Development of Ancillary Skills  Textiles  Storage need  Pottery  Pyrotechnology  Metallurgy (primarily copper)  Fermented beverages

26. Spring, 201126 Fall, 2010 26 The Pace  4000 BCE  Metal use is common  2000 BCE  Bronze developed  1500 BCE  Iron extracted  900 BCE  Preservation of Dead

27. Spring, 201127 Fall, 2010 27 Metals  Metals used by virtually all civilizations  Most metals exist as ores  Found combined with O, S, and halogen  Cu, Au, Ag  Cu – most abundant, found in all early civilizations  Au – very soft, useless for all but jewelry  Ag – rarer and more costly than Au

28. Spring, 201128 Fall, 2010 28 Copper  Became inexpensive  Blue rocks  Produced Cu metal  On heating  Wood fire  Soft for use

29. Spring, 201129 Fall, 2010 29 Bronze  Mixing Cu and Sn - alloy  Harder than Cu  More durable edges  Sharper  Bronze Age – metal used as tools, weapons, and armor  Fe was known, but very rare  Found in meteorite remnants

30. Spring, 201130 Fall, 2010 30 Iron  Fe more firmly bound in ores than Cu or Sn  Wood fire is insufficient to smelt Fe  Hittites discovered well ventilated charcoal fire could smelt Fe  Wrought Iron – (Fe) is brittle  Adding C produced the alloy steel  Armor and weapons were first developed

31. Spring, 201131 Fall, 2010 31 Iron Age  Dorians  Barbaric Greek tribe  Conquered Mycenaean Greeks  Using steel weapons (Fe + C)  Greeks moved into Asia Minor  Known as the Philistines  Finally defeated by steel equipped Israelites under King Saul

32. Spring, 201132 Fall, 2010 32 Egypt  Practical chemical arts – very advanced  Embalming and preservation of dead  Metallurgical expertise  Developed use of pigments  Mineral and plant infusions  Where does the word Chemistry come from?  Kham = Egypt, derived into khemeia (Art of Egypt)  Khumos = plant juice (Greek)

33. Spring, 201133 Fall, 2010 33 The Greek Elements  Nature of the universe  Structure of materials  Philosophers (lover of wisdom)  Studied the “why”  Chemical theory  Thales – first recorded Greek philosopher  “can a substance be changed from one material into another?”  Blue stone – heat became red Cu  “Can any substance be changed into another?”  “Are all substances different aspects of one basic material?”

34. Spring, 201134 Fall, 2010 34 Water - Element  Greek philosophers  There is a basic substance  Water was disputed as that substance  Sky was not a semi-sphere, but a complete sphere  Earth was spherical as well  Vacuum could not exist  Sky contained air (experience)  Air – element of the universe

35. Spring, 201135 Fall, 2010 35 Fire  Element should be something that changed  Fire  Ever shifting  Ever changing  Fieriness made change possible

36. Spring, 201136 Fall, 2010 36 Change  Persians conquer Greece  Rule was harsh  Scientific thought was suppressed  Philosophers moved west  Pythagoras went to Italy  Founded a substantial school  Empedocles, Sicily, eminent scholar  Why was there a single element?

37. Spring, 201137 Fall, 2010 37 Four Elements  Fire, Air, Water, and Earth  Accepted by Aristotle  Combination of Properties  Fire = hot and dry  Air = hot and moist  Water = cold and moist  Earth = cold and dry

38. Spring, 201138 Fall, 2010 38 Where did Aristotle come from?  Socrates  Son of a working class family  Set about establishing rules for an ethical society  An irrefutable truth  Doesn’t work well in chemistry  Nature dictates the rules  Natural philosophy was not a good thing to study

39. Spring, 201139 Fall, 2010 39 Where did Aristotle come from?  Socrates  Rejected experimentation  Rejected proof by analogy  Rejected proof by inductive reasoning  Conclusions reached through mental reflection  Deductive reasoning (Socratic method)  Damaged the development of chemistry  Sentenced to death for corrupting the youth  Left star pupil Plato behind

40. Spring, 201140 Fall, 2010 40 Where did Aristotle come from?  Plato  Son of a wealthy family  Father claimed to be the son of Poseidon  Natural philosophy was worthy of study  Remove atheism and retribution  Natural laws are subject to the authority of divine principles  Metals are referred to as waters  They melt  Materials can be transmuted  Founded the Athens Academy  Philosophical and scientific teaching  Best student was Aristotle

41. Spring, 201141 Fall, 2010 41 Aristotle  Four Elements  Heavenly bodies did not appear to change  Properties must be different  Composed of a fifth element  Ether (glow)  Ether was perfect, eternal, incorruptible  Four earthly elements were very different  These ideas lasted for 2000 years

42. Spring, 201142 Fall, 2010 42 Ideas Are Still Present in Our Language  Raging of elements for a bad storm  Fifth element (ether) = quinta essentia in (Latin) = quintessence = purest form of something

43. Spring, 201143 Fall, 2010 43 Divisibility of Matter  Stone fragments  Each piece can be made smaller  Still stone  Can this go on endlessly?  Leucippus  Eventually you cannot get smaller  Democritus (student)  Ultimately small particles are “atomos”  Meaning indivisible  Atomism is this doctrine

44. Spring, 201144 Fall, 2010 44 Atoms  Each atom of an element has distinct size and shape  Materials Greeks knew  Mixtures of atoms of the different elements  One substance changes into another  Alter this mixture of atoms  Recall: Greeks did NO experimentation  Conclusions were reached  Arguments from first principles  Atomism was rejected by Aristotle

45. Spring, 201145 Fall, 2010 45 Aristotle  Thoughts pervasive for 2000 years  Epicurus made atomism part of his thought  Titus Lucretius Carus – Roman poet  Didactic poem (teaching poem)  De Rerum Natura (On the Nature of Things)  Wrote of the atomist view  Scraps and bits of quotations remained  Aristotle’s view prevailed

46. Spring, 201146 Fall, 2010 46 Why did Aristotle’s philosophy hold sway for so long?  Thoughts had an intuitive appeal  Tutored the son of Philip of Macedonia  Alexander the Great  Conquered most of the known world  Spread Greek culture and philosophy  China to Spain

47. Spring, 201147 Fall, 2010 47 Greeks  The greatest philosophers  Greek hypotheses  Concerning the nature of matter  Concerning the interactions of matter  No experimentation  Hindered chemical advancement

48. Spring, 201148 Fall, 2010 48 Theory and Practical Arts  Egypt – applied chemistry  Greek – theoretical approach  god Thoth was source of chemical knowledge  Associated with Hermes  Mysticism and science relationship

49. Spring, 201149 Fall, 2010 49 Mysticism and Chemistry  Khemeia associated with religion  Practitioners were feared  Priests – knowledge of the gods  Astrologers – knowledge of the future  Chemists – ability to change substances  Used by individuals to increase power

50. Spring, 201150 Fall, 2010 50 Examples  Seven planets were associated with the seven known elements  Gold, silver, copper, iron, tin, lead, and mercury  Kept chemical changes obscure  Retarded progress  Anyone could pretend to be a practitioner

51. Spring, 201151 Fall, 2010 51 First Practitioners  Bolo of Mendes  Studied changing lead (Pb) into gold (Au)  4 elements suggested the possibility  Red rock gave Fe  Could Fe give Au?  Need the correct process

52. Spring, 201152 Fall, 2010 52 Transmutation: Pb to Au  More profitable to fake the change  Cu(Zn) alloy – brass  Yellow like Au

53. Spring, 201153 Fall, 2010 53 Rise of Christianity  Khemeia was considered pagan  Forced underground  Greek learning left Rome  Nestorians, Christian sect, persecuted by orthodox Christians  Moved to Persia  Bringing Greek learning with them

54. Spring, 201154 Fall, 2010 54 Arabic Learning  Rise of Islam  Arabs burst into western world  Invaded North Africa, Egypt, and Persia  In Persia – met Greek science  Very interested  May have been practical  Stopped at Constantinople due to Greek Fire  Burned in water  Callinicus (Egypt) practiced khemeia  Khemeia became al-kimiya in Arabic (al = the)  Became Alchemy  300 BCE to 1600 CE

55. Spring, 201155 Fall, 2010 55 Why not Europe?  300 – 1200 CE – nearly complete blank  300 – 1100 CE – height of Arabic learning  Preserved and extended Greek-Egyptian  Many chemical terms from this period  Alcohol, alkali

56. Spring, 201156 Fall, 2010 56 Transmutation  Greeks suggested a need for a dry powder  Xerion = dry  al-iksir = dry in Arabic  Became elixir in English  Philosopher’s stone  Philosopher was a scientist

57. Spring, 201157 Fall, 2010 57 The Elixir  Changed base metals into Au  Cured all diseases  Conferred immortality  A new pursuit  Persian Alchemist – Al-Razi  Pursued medicine

58. Spring, 201158 Fall, 2010 58 Europe’s Revival  Switch to medicine in Arab world  Led to decline of interest in alchemy  Arabs translated many Greek texts in Arabic  Military incursions by Turks and Mongols  First Crusade in 1096 captured Jerusalem  European presence in Middle East for 200 years  Christians retook Spain  Blended European and Moorish civilizations

59. Spring, 201159 Fall, 2010 59 Europe’s Revival  Translated Arab text into Latin  Gerbert (French Scholar) later Pope Sylvester II encouraged this work  Others followed  By 1200 alchemical knowledge was available to European Scholars  Albert of Bollstadt (Albert the Great)  Studied Aristotle  Given credit for discovering Arsenic  Roger Bacon

60. Spring, 201160 Fall, 2010 60 Roger Bacon  Today he is known for the idea that experimentation and mathematics would advance science  Not widely accepted during his life  Wrote a universal encyclopedia of knowledge where he described gunpowder  Did not discover it  Permitted its use to bring down medieval order  Earliest symbol of use of technological proficiency  Allowed Europe to conquer much of the world over the next 5 centuries

61. Spring, 201161 Fall, 2010 61 Political Changes  Constantinople – sacked by the Crusaders  Most of Greek work was lost  City was recovered by Greeks  City was lost to Turks where it remains  Compass discovered  Led to great voyages of discovery  Europeans no longer felt Greeks knew it all  Printing press was invented  Unpopular views could not be suppressed simply by not copying the work

62. Spring, 201162 Fall, 2010 62 Impact of Science  Polish Astronomer  The Earth is not the center of the universe  View held by the Greeks  Accepted by Western World  Nicholas Copernicus  Flemish Biologist  Portrayed human anatomy with great precision  Refuted much of what the Greeks thought  Andreas Vesalius  Began the Scientific Revolution

63. Spring, 201163 Fall, 2010 63 End of Alchemy  Shift from pursuit of Au to medicine  Georg Bauer, German  Summarized all practical knowledge of metallurgy  von Hohenheim  Purpose of alchemy is to prepare medicines  Too much profit in pursuit of minerals and medicines to waste time on the pursuit of Au

64. Spring, 201164 Fall, 2010 64 Modern Chemistry  Astronomy  careful measurement and mathematics  since ancients  Physics  careful measurement and mathematics  Since 1590  Chemistry  since 1750

65. Spring, 201165 Fall, 2010 65 Chemistry  Late 18 th Century  Sought an understanding of matter  Philosophy changed into Science  Before: Air – an element  After: Air – a mixture of gases; individual gases were discovered  Curiosity, careful observation, experimentation, measurement, and publication

66. Spring, 201166 Fall, 2010 66 Important Chemists  Joseph Black –  air was a mixture of gases; discovered carbon dioxide  Henry Cavendish –  discovered hydrogen  Daniel Rutherford –  discovered nitrogen  Scheele, Priestly, Lavoisier  discovered oxygen  Antoine Lavoisier –  father of modern chemistry – placed great importance on careful measurements and the Law of Conservation of Mass  Joseph Proust –  the Law of Definite Proportions  John Dalton –  atomic theory, Law of Multiple Proportion, chemical symbols  A Meyer, Dimitri Mendeleev –  the Periodic Table

67. Spring, 201167 Chemistry Today   Physical Science   Includes – –Chemistry – –Physics – –Astronomy – –Geology   Biological Sciences

68. Spring, 201168 Chemistry Today   Chemistry – –Analytical Chemistry – –Biochemistry – –Inorganic Chemistry – –Organic Chemistry – –Physical Chemistry

69. Chemistry Today Spring, 201169 Energy Materials Chemical production Pharmaceutical Cosmetic Medical Criminal Justice Legal Environmental Agriculture Food Chemistry