early chemical history -...
TRANSCRIPT
Early Chemical History
Some cool old stories about howchemistry came to be!
Rhonda Reist
400 BC - Greeks
The first to try toexplain why chemicalchanges occur.
Democritus
Greek philosophernamed Democrituswas the first todiscuss anindivisible particlehe called an ATOM.
Eventually there became the ideathat there were 4 types of “atomos”
Earth Air
Fire Water
Next 2000 years . . .
“Chemical” history wasdominated by ALCHEMY - the belief that you could turn less valuable metals into gold!
Sort ofbrings upthe image ofa MedievalWizard!
But alchemy didn’t originate in Europe.
It It came from the Middle East
One of the earliest“alchemists” was a Muslim“philosopher named Jabir.
The techniques came toWestern Europe following the
first Crusades.The Egyptian and Arabsknew of many ways tochange substances bymixing and heatingvarious combinations ofmaterials.
Famous paintingof an alchemist
in his lab byJoseph Wright of
Derby.Searching for
the “philosophersstone”. . .
He probably hadmade someelemental
phosphorus.
AnAlchemist’s
lab inFrance.
Another Alchemist’s Lab
Welcome toPotionsClass!
Alchemy was somewhat good.
It resulted in thediscovery of many new
ELEMENTS andCOMPOUNDS.
However, the alchemistswere very secretive & muchof their work was written in
strange code!
Often the alchemists “language”was in strange code!
An actual alchemical text in Switzerland.
Plus, it was just plain
WRONG!
Some advancements that helpedmove along the nature of
chemistry - things that reallyhelped the cause . . . .
1500’sGeorg BauerDevelopedMETALLURGYHow to getmetals out oftheir ores.
1500’sParacelsus
Swiss alchemist &doctor. Actually curedsome people!
Worked withMEDICINALminerals.
Medieval Hospital1500’s
In Beaune, France
A medieval pharmacy in France.
Samplemedications
in amedievalhospital
pharmacy.
1600’s
Some contemporaries: Shakespeare Galileo Newton Elizabeth the 1st just ended her reign.
Robert Boyle - English or was he Irish?
First “Chemist” to performQUANTITATIVE
Chemistry while studying therelationship between pressure &volume of gas or was it Hooke
that really did the work?
A foundingmember of theRoyal Society &VERY VERYWealthy!
At this time theonly the richcould afford todo scientificresearch- thewas no Fermilab!They wereknown as “Natural Philosophers”.
Robert Boyle - English
Was one of the firstpeople to suggest the
idea of an ELEMENT; orbasic “building piece”.
Robert Boyle’s book
“The ScepticalChymist”
One of the first“chemistry books”
Robert Boyle - English
Still thought that metalsweren’t ELEMENTS &
therefore could bechanged into other metals .. . An ALCHEMICAL belief.
1700’s
George StahlGerman
(1660-1734)Was studying
COMBUSTION
Suggested that whensomething burned it released
a substance calledPHLOGISTON.
1700’s
PHLOGISTON was a VERYpersistent idea!
He thought that when youburned something in a closedcontainer it eventually wentout because the air in the
container becamesaturated with
PHLOGISTON.
But there was a problem . . .
When some metals would burnthey would get heavier!
This contradicted thephlogiston theory!
The belief in the substancephlogiston
caused a big slow down inchemical discoveries!
A BIG slow down!
Joseph Priestley
1733-1804BritishTruly was a minister! A “dissenter”.Friend of Ben FranklinLived above a brewery!NOT a wealthy man
Greatexperimentalist!
In the late 1760’she found that youcould dissolve“fixed air” akacarbon dioxide intowater making…
Soda water orcarbonatedwater! POP!
Is credited with discovering
OXYGENHe had heated various metal “calxes” &
noticed that the gases produced caused aflame to burn very brightly!
Also noted that mice breathing this “air”could stay alive much longer than in regular
air.
Since substances could burnvery well in oxygen
Oxygen was originally called
“DEPHLOGISTICATEDair”
Then the big revolutionhappened!
France 1734-1794
Antoine Lavoisier
Lavoisier!The Man!
and his coolwife Marie
Copy ofLavoisier’s most
importantpublication.
Finally explained the true nature of
COMBUSTIONand killed of the
PHLOGISTON theory!
He did this with the help of VERYaccurate
MEASURING devices.
He had the best balances in the worldfor a number of years!
Lavoisier carefully weighed thestarting substances: REACTANTS
& ending substances: PRODUCTS
of reactions ¬iced thatthey werealways the
SAME!
Showing that “matterwas neither created or
destroyed” in achemical reaction . . .
this is called the
LAWOF
CONSERVATIONOF
MASS
Leather “gasbottles”
Pneumonic trough to collect gases.(It’s as big as your table!)
Lavoisier’s great burning lens!
What a dork!I had to prove I was there!
Lavoisier’s Face Shield!
Yeah! People keep usingbalances!
Joseph PROUST(1754-1826)
French
Did tons of work with iron andcopper compounds
Did tons of work with iron andcopper compounds
Noticed that in “a given compoundalways contains the same
RELATIVE MASSESof elements . . . It didn’t matter
where the compound came from.
For example: copper carbonate
5.3 parts copper4 parts oxygen1 part carbon by mass
This is now called the
LAWOF
DEFINITEPROPORTIONS
JohnDaltonBritish
(1766–1844)
Super bright &intelligent buthe was really a
huge geek!
Startedwonderingwhat couldcause the
Law ofDefinite
Proportionsto be true.
Dalton noticed that other compoundscombined in predictable ways . . .For example, the mass of oxygenthat combined with 1.0 g carbonCompound 1 1.33g oxygenCompound 2 2.66 g oxygenSuggested that you could have
CO and CO2
Dalton developed the
LAW OFMULTIPLE
PROPORTIONSfrom this.
When 2 or moreCOMPOUNDS are made
from the sameELEMENTS
They will always combinein ratios of
WHOLE NUMBERS.
Suggestedthat the
compoundswere made
of tinybuilding
pieces called
ATOMS
Symbols fordifferent
Elementsused byDalton
This idea was not widelyaccepted for MANY years!
• Major paper onatoms waspublished in 1804
• People were stillarguing it 100years later!
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
1. Each ELEMENT is made up of tiny indivisible particles called ATOMS.
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
2.The atoms of a given element are IDENTICAL; the atoms of different
elements are DIFFERENTin some FUNDAMENTALway.
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
3. Chemical COMPOUNDS are formed when atoms COMBINE with each other.
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
3 cont.A given compound alwayshas the same RELATIVENUMBERS and types ofATOMS.
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
4. Chemical reactions involve RECOMBINATIONS of atoms.
Dalton’s Atomic Theory(the first actual explanation of how “chemistry” worked)
4. cont. The atoms themselves
are NOT CHANGED in a chemical reaction.
Amazingly,
most of this theory(explanation) remained
unchanged until about 1900when radioactivity was
discovered.
ASSIGNMENT!Read more Curieand Beccquerel andthe “radioactivewalk” in Paris.Send Lee Marek $5
Becquerel
Curie