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 &noticed 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