exam # 1 friday, 24 february individual classrooms
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Exam # 1 Friday, 24 February Individual Classrooms. Early Ideas About Matter. Motion - Matter. Gravity universal property of all matter strength of attraction is function of mass, regardless of material Fundamental property to distinguish different types of matter -- ? --. - PowerPoint PPT PresentationTRANSCRIPT
Motion - Matter• Gravity
– universal property of all matter
– strength of attraction is function of mass, regardless of material
• Fundamental property to distinguish different types of matter
-- ? --
Structure & nature of matter changes when:
• Wood burned
• Foods cooked
• Clays fired to make bricks and pottery
• Metals smelted
Where do metals come from?
• A few metals occur naturally in metallic form - Gold and silver deposits were found in ancient times
Where do metals come from?
• Most metals occur in ores– Ores are more like earths (dull, brittle) than like
metals
Iron ore Lead ore
Smelting metals from their ores
– Ores must be processed to yield pure metals– Only a small percentage of metal yielded
• copper ore and modern man’s inept attempt at smelting
Alloys
• Combination of metals
• Better properties– Lower melting point– Stronger, less brittle
• Example: Bronze– Alloy of copper and tin
Bronze Age (3500 BC)
~ tin/copper alloy
~ copper & tin deposits only in certain areas
~ strong easily worked
Iron Age (1500 BC on)
~ found all over
~ can be sharpened; hard and tough
~ difficult to work
~ required hot furnace & special techniques
Pottery
• Fired clay – from 6500 BC?
• Certain clays used– at certain temperature– for certain times
• Patterned, pigmented
Glass
• Melted sand• Certain sands used• High temperatures• Blown, molded• Earths, metals added color, strength
Ancient Roman glass jug
Other crafts practiced since early times
• Pigments
• Dyes
• Perfumes
• Fermenting drinks
• Tanning
• Cooking
• Ancient peoples distinguished many different materials
• Engineers and artisans had developed many material technologies
• These technologies were applied to specific materials for specific purposes
Early Chemical Technology
Unification
• Huge diversity
• Fundamental principles exist?
• Which properties important?
• Categorization
Another Classification Scheme for Matter
MATTER
Pure Substances Mixtures
Homogeneous Mixtures
Heterogeneous Mixtures
CompoundsElements
Atoms Combine to Form Molecules
• Most materials are made of more than one type of atom
• Chemical formula gives atomic makeup – Water is H2O
– Ammonia is NH3
– Glucose is C6H12O6
What Determines Chemical Properties of Each Element?
• Usually, # of protons = # of electrons • Electrons tend to fill shells surrounding nucleus • Outer shell stability
Chemical Reactions Rearrange Atoms
• Number of atoms does not change – Reactants have same atoms as products
• Only arrangement of atoms change – Different molecules after reaction
• Methane + oxygen gas carbon dioxide + water– CH4 + 2O2 CO2 + 2H2O
– One carbon, two oxygen, four hydrogen (before & after)
Thales(640 – 546 B.C.)
• Basic element is water
• In greatest quantities
• Found as solid, liquid, and gas
Nature of matter: One basic substance
Anaximander
All matter from one “boundless something” that contained all qualities (wet/dry; hot/cold)
Nature of matter: One basic substance
Anaximenes(570 BC) - Air is the one basic substance - All space above Earth is air.-Compress air to form denserwater and earth
Hericlitus (540 – 475 B.C.)
• If change characterized the Earth . . .
• Basic element must be changeable
• That element must be fire
Wood reveals its composition when it burns:
• fire issues from it
• water oozes from it/hisses
• air (smoke) is produced from it
• earth (ashes) remain behind
Each different kind of matter is a combination of two or more elements in particular proportions, for example …
Four Elements / Four Qualities of the Ancient Greeks
• Elements had four qualities:
Dry vs. Moist & Hot vs. Cold
• Qualities combined in various pairs to form the different elemental components of the Earth
Matter
• marble
Form
• shape
Matter
• 4 elements
Form
• specific combination of elements
Statue
Individual Elements
One element to another element
• Change qualities = change 1 element into another element
Elements themselves were interchangeable: Water air when it evaporates
(wet-cold wet-hot)
Air water when it rains(wet-hot wet-cold)
Four elements and alchemy
• Aristotle’s four element theory was to exert a considerable influence on the practice of alchemy and the idea of transmutation
Transmutations• Alter proportions of elements =
change one type or matter into another.
Idea carries over into alchemy:
Transmute a cheap metal into gold by
adjusting proportions of the four elements
Greek “Atoms”
• Question of divisibility of matter
• Break a stone and it is still a stone
• Leucippus (c. 450 B.C.) eventually no further division
Democritus (470 – 380 B.C.)
• Atomos – indivisible – move in empty space (void)
• One fundamental material
• Many different sizes and shapes gave different properties to elements
• Aristotle wins – atomist idea died out
Beginnings of Alchemy
• Emphasis on degrees of purity/nobility
~ Gold most pure and noble
~ “Maturation” of minerals in ground
• Incorporated Aristotle’s four elements
• Greek Philosophy – Egyptian craftsman
Transmutation as goal of Alchemy(wealth – longevity – immortality)
• Chemical
~ transform base metals silver / gold
• Physiological
~ Sickness Health
~ Old-age Youth
~ Earthly Supernatural Existence
The Alchemical Tradition
• Origins: ~ Greece (Hellenistic) ~ China ~ India
• Further developed by Arabs • Inherited by medieval Europeans • Part practical chemistry, part spiritual
quest
Hellenistic Alchemy
• Transmutation of base metals to gold
• Spiritual Purification
Hermes Trigmegistus
Eastern/Chinese Alchemy
• Independent of (and prior to?) Western alchemy
• Gold is eternal and healing, led to medical alchemy:
• Search for the “Elixir of Life,”
• Soluble “potable gold” (400 BC) a potion for eternal life
Arab/Islamic Alchemy
• Arabic alchemists – add mercury and sulfur
• Used “al-iksurs” (colored “seed” catalysts) in transmutation attempts.
• Arabic alchemists – philosopher’s stone to stimulate transmutation
• Combustible principle = phlogiston theory
Importance of Medicine
• Problems: crowded, unsanitary, infested homes; contaminated food/water; low life expectancy.
• Physicians in medieval Europe
- Most followed ideas of Hippocrates (460-370 BC) and Galen (129-200 AD).
- Disease = imbalance in 4 body humours.
• Inorganic substances and alcohol could fight infection, but not favored by Galenists.
Ibn-Sina/Avicenna ( 980-1037)
• Greatest physician of his time
• Believed in Four Elements but not transmutation.
• Contributions:~ dosage effect of drugs~ Had idea that chemicals maintain identity even when combined
Paracelsus (1493 – 1541)• At odds with the dominant
medical establishment
• Disease spread between persons (external cause?) contrary to Galen’s ideas
• Founded Iatrochemistry (Alchemy for medicinal purposes)
• Iatrochemist’s legacy – legitimacy of chemistry
Paracelsus’ idea of elements and principles
• Three Elements (Fire, Air, Water) and Three Principles of Earth (sulfur, mercury, and salt)
• Wood burning: “That which burns is sulfur, that which vaporizes is mercury, and that which turns to ashes is salt.”