“Leaves That Are Green” written by Paul Simonperformed by Simon and Garfunkel

 I was twenty-one years when I wrote this song.

I'm twenty-two now but I won't be for longTime hurries on.

And the leaves that are green turn to brown,And they wither with the wind,And they crumble in your hand.

 Once my heart was filled with the love of a girl.

I held her close, but she faded in the nightLike a poem I meant to write.

And the leaves that are green turn to brown,And they wither with the wind,And they crumble in your hand.

 I threw a pebble in a brook

And watched the ripples run awayAnd they never made a sound.

And the leaves that are green turned to brown,And they wither with the wind,And they crumble in your hand.

Elements and some compounds that are gases Where to find gases in the periodic table

Properties of Common Gases

Do not memorize this list, just look over the list and the rest of this list on the Blackboard website.Use this for reference, especially for the gases you see in lab.

How to Identify a Gas by Its Formula

Foundations of Chemistry: Understanding Combustion and GasesJoseph Priestley and Antoine Lavoisier

Joseph Priestley 1733-1804

• The genius Priestley studied and taught about ten languages, both modern and ancient. (Greek, Latin, Hebrew, Arabic, French, Italian, and High Dutch, etc.)

• Son of a non-conformist preacher, he became one of the first Unitarian ministers.

• Hired by Earl of Shelburne as librarian and literary and scientific consultant.

Franklin encouraged Priestley to study science• Benjamin Franklin convinced his friend,

the genius Priestley to to study electricity and to write a book summarizing what is known of electricity. Franklin was too busy to write it himself (printer, inventor, scientist, author, satirist, chess-player, politician, diplomat, ladies’ man, etc.)

• Priestley wrote a book summarizing all that was then known about electricity. (“The History and Present State of Electricity, With Original Experiments”)

1761 1769

Origin of the Pneumatic Troughto collect gas under a liquid

by Stephen Hales, 1727

About 1727, Stephen Hales discovered a method to isolate gases by bubbling the gas into a filled container of liquid, usually water (using a bent gun-barrel).

Use of a pneumatic trough to collect gaseous oxygen over water

Joseph Priestley’s study of chemistry of gases• Using Hales’ pneumatic

trough with Hg, Priestley isolated and tested many new gases (NH3, HCl, H2S, etc.)

• Priestley lived next door to a brewery (at Leeds) and from observing carbon dioxide bubbles, he invented carbonated water, seltzer.

• He gave those rights to a friend, Jacob J. Schweppe.

Jacob J. Schweppe

Joseph Priestley

Enlarged picture

Priestley’s pneumatic trough for collecting gases under water and testing those gases. Two mice are in the ventilated bell jar in the foreground.

Priestley’s pneumatic trough for collecting gases under water and testing those gases

Priestley’s pneumatic trough to collect water-reactive gases under mercury.Under Hg, Priestley isolated and studied ammonia, hydrogen chloride, hydrogen sulfide,

sulfur dioxide, nitrogen monoxide, and nitrogen dioxide. He was very skilled at experimental work.

“Flame releases phlogiston”

• A candle lit under a bell jar soon is extinguished because the air becomes completely fully phlogisticated [or because the oxygen is depleted].

Phlogiston: A mistake that put ideas backwards?or an advance that led to its own disproof?

Priestley’s pair of burning lenses

Priestley’s Bell Jar apparatus

• Heated by the sun’s rays through a burning glass, “calx of mercury” (HgO) releases “dephlogisticated air”.

• 2 HgO 2 Hg + O2

• The lighted candle uses “dephlogisticated air”

Dephlogisticated air [Oxygen]

• Priestley was best known for his isolation and study of what he called “dephlogisticated air”, now know as oxygen.

• He said mice lived well in it and breathing it made him feel “light and easy”.

Priestley’s experiments on gases breathed by mice and plants

Carbon-Oxygen CycleOne of the Biogeochemical cycles

Plant Animal

Element cycles like this were suggested both by Priestley and Lavoisier.

Experiments on Air by Priestley, 1774

Chicago & Savannah parksalso Edinburgh, Scotland (the “new” city)

• Due to the theory that animals and people need oxygen (and plants supply oxygen), new cities were constructed having a network of parks.

• Older European cities did not have such parks.

• Also started the tradition of bringing plants (flowers) to those in any hospital.

Savannah, GeorgiaChicago parks

Fiery liberal in religion and politics, but very conservative in chemical theory

• Scholar, Theologian, Scientist

• One of the Founders of the Unitarian religion

• Supporter of the French Revolution

• Opponent of all monarchies

• Favors Freedom of Conscience (very controversial at that time)

Dr. Phlogiston

A caricature of Priestley :

A Caricature of Priestley calling for the King’s head

It was alleged that he was going to call for the king’s head at a Bastille day party held by English supporters of the French Revolution, July 1791.

Royalist mob burns Priestley’s house & lab, July 14, 1791

Northumberland

Priestley died insisting that phlogiston was correct In 1800, four years before his death,

Priestley wrote the book, “The Doctrine of Phlogiston established, and that of the Composition of Water Refuted. [Theory of Oxygen Disproved].

When you read a statement in an encyclopedia that says, “Priestley discovered oxygen.” If you listen carefully you can hear Priestley’s voice saying, “No, I definitely did not.”

When the discovery of bromine, the only non-metal that is liquid at NTP,Justus Liebig went to his lab shelf and took down a bottle he had labeled

“Iodine chloride” and found it had the same properties as the newly announced element. Liebig then placed that bottle in his “cupboard of mistakes”.

Antoine J. Balard (1802-1876)discoverer of bromine

Iodine monochloride, ICl, does existand can be made by heating I2 with Cl2

Priestley insisted on the wrong concept.When you are wrong, it is not almost correct.

No one claims claims Liebig should be given priority for discovering bromine. Balard gets credit because he not only isolated bromine, but also convinced everyone that it was an element.

Priestley Medal

• The highest honor given by the American Chemical Society is the Priestley Medal.

Monsieur Lavoisier and his Wife

• Famous painting made about 1788 by Jacques Louis David (best French painter of that time, who also painted French revolution, Napoleon, Marat, etc.)

• Original is in Metropolitan Museum of Art, New York (oil on canvas, 8’8” x 7’4”)

• His wife Marie was a student of painting with David.

• Marie was a child bride, married at 13 years old, but a very intelligent and talented child.

Marie Anne Pierette Paulze

• Marie spoke and read several languages, including English.

• She translated many English scientific papers for Antoine, who did not read English.

• A talented artist, she drew all the diagrams for Antoine’s books and papers.

• A gifted partner who was allowed to participate in the science more than any female of her time.

Portrait of Benjamin

Franklin painted by his friend,

Marie Lavoisier

Antoine Lavoisier 1743-1794

• Lawyer, Accountant, Scientist• A Scholar in the Age of

Enlightment• The Founder of Modern Chemistry• First to explain oxygen and

disprove phlogiston• Only 1/5 of air supports animal life

(and fire) and is very reactive.• Other 4/5 is Azote (A = not, zo or

zoo = animal life), the gas now called Nitrogen (nearly inert).

Antoine’s Early work in geology and water analysis

• Lavoisier trained with the geologist, Guettard

• This is Lavoisier’s diagram of the geological strata.

• Lavoisier worked on the first geological map of France.

Modern Geological map of France

The Crucial Experiment• From discussion with Priestley,

Lavoisier learns that when heated “mercury calx” releases “dephlogisticated air”.

• Lavoisier obtains a sample and repeats the experiment.

• 2 HgO 2 Hg + O2

Modern experiment heating orange HgOcondenses shiny droplets of liquid mercury above.

Apparatus for heating HgO

• Reversible reaction with measurements led to the theory of oxygen and disproved the theory of phlogiston.

• He used closed systems and weighed all reactants and products.

Lavoisier improves and reinterprets Priestley’s experimentdisproving phlogiston and establishing oxygen as an element

• Heating “mercury calx” (HgO) released a gas (oxygen).

• Heating the mercury liquid strongly caused the mercury to react with the gas to reform HgO (a reversible reaction).

• All the material weights could be accounted for.

• No phlogiston was detected or needed.

Oxidation and reduction are addition of oxygen and addition of phlogiston.

Experiment with Pneumatic TroughMarie takes notes

Lavoisier reinterprets Cavendish’s experiment

• Cavendish discovers hydrogen and find that it is flammable.

• Cavendish thinks hydrogen is pure phlogiston.

• Lavoisier sparks Hydrogen with Oxygen and collects and weighs the product Water.

Lavoisier proves water is a compound, not an element.

• The actual glass bulb used by Lavoisier to spark Hydrogen with Oxygen to form Water.

• This Apparatus is today in the Museum of Arts et Metier in Paris.

Lavoisier emphasized weighing• Like Newton, Lavoisier

emphasized weight and mass.• Lavoisier provided a path to find

new elements: weigh everything in a sample, any weight unaccounted for might be a new element.

• Unlike his French predecessor, Descartes, who emphasized volume (extent) rather than mass.

• Following the French tradition of emphasis on volume:

• Gay-Lussac invented the burette.• Dumas invented constant volume

bulbs to measure gas density.• Gravimetric vs. Volumetric analysis

Tschirnhausen’s huge burning glass used by Lavoisier to prove that diamonds burn and release only carbon dioxide

Lavoisier was also first to burn fuels with oxygen to reachvery high temperatures

Lavoisier’s work as public servant for the French Kings (Louis XV and Louis XVI)

before the French revolution• Lavoisier worked on several committees: salt, gunpowder, taxation (he

suggested the Paris wall to prevent smuggling and tax evasion)

• As an economist, lawyer, and scientist, he was valuable on all these committees.

• He was not the chairman, but the secretary who took notes, made summaries, and wrote the reports for the king.

• When he started working on the gunpowder committee, France had a shortage of gunpowder and what they had was of poor quality.

• Before he finished, France had an abundance of gunpowder said to be of the best quality anywhere. (That gunpowder was later used by Napoleon.)

• One of Lavoisier’s students, Eleuthère Irénée du Pont, went to America and founded a gunpowder and chemical company, DuPont.

Lavoisier’s masterpiece

• Textbook, “Elements of Chemistry”, 1789

Lavoisier used Boyle’s definition: an element is a substance that cannot be decomposed to simpler substances.

Painting of Robert Boyle

Lavoisier’s List of Elements

• First list of Elements to agree with many of our modern elements

• First two (light & heat) are not material elements.

• Some were later decomposed (as predicted by Lavoisier), e.g. lime (CaO) and magnesia (MgO), silex (silica, SiO2)

• All non-alloyed (pure) metals (15 listed by Lavoisier) were discovered to be elements. Before Lavoisier, all metals were thought to contain phlogiston, thus they were considered compounds, not elements.

Improving Nomenclature• “We cannot improve the

language of any science, without, at the same time, improving the science itself.”

- A. Lavoisier, 1787• Every substance should have

only ONE name.• Each element should be named

for its most important property. (others named elements for their country)

• Each compound must be named from its composition, e.g. , magnesium bromide.

• For compounds this was modeled after Linnaeus’ biological binomial nomenclature.

Chemical names before Lavoisier’s systematic nomenclature

Lavoisier’s new names for the gases

Lavoisier’s apparatus for combustion analysis

Combustion analysis was greatly improved by Berzelius and the German chemists, but all the methods were exemplified in Lavoisier’s book.In order for chemistry to advance chemists had to understand combustion and gases.Oxygen reacts directly with all elements except the noble gases and the noble metals.So, Berzelius measured the atomic weights of all known elements by their oxides.

Apparatus as drawn by Marie

Another Lavoisier experiment on which gases are breathed in from air and which gases are breathed out from air by a human. Respiration

Ice Calorimeter

• To measure amount of heat released by reactions and other processes

• Designed by Antoine Lavoisier and his friend Pierre-Simon Laplace, now famous as a mathematician.

• Measures by amount of ice that melts, by opening spigot to collect melt water. (Not adiabatic as most modern calorimeters, but isothermal.)

• Lavoisier medal is awarded by the International Society of Biological Calorimetry.

Accomplishments of Antoine Lavoisier

Lavoisier’s Accomplishments, part 2

Some biographies and Wikipedia claim that Lavoisier did not discover any new elements, but that he was essential in convincing chemists of the correct interpretations. Not only did Lavoisier give the correct interpretation of oxygen, but he also convinced scientists that fifteen metals were elements. Before Lavoisier, metals were considered important, but they were not elemental as they contained a common factor of metallization, phlogiston. In my view, Lavoisier can be considered the discoverer of fifteen metallic elements.

17

Paul Goodwin as Lavoisier, Lucy Davenport as Marie in the play, “Oxygen”

Lavoisier arrested (or was he?)

The guillotine was kept busy during the “Reign of Terror” of the French Revolution

Lavoisier was tried, convicted, sentenced,and executed, all on the same day, May 8, 1794.

“It took them only an instant to cut off his [Lavoisier’s] head, but France may not produce another like it in a century.” - Joseph-Louis Lagrange, French mathematician

What if Lavoisier had lived a little longer?

Lavoisier died at age 50 at the height of powers. He could have taken a vacation abroad to escape the most unstable time of the “Reign of Terror”. But he did not expect the depth of hatred directed at the “Tax Farmers” and he did not know he would face Marat among the judges. Had he lived longer, he would have met John Dalton, Alessandro Volta, Humphrey Davy, Jons Berzelius, Gay-Lussac, and perhaps Amadeo Avogadro.Lavoisier had planned another volume of Traite Elementaire de Chemie.

Combustion notes online

Bunsen burner flame with and without air supply

Sooty flame

No soot in flame,burns off soot

Hottest point is the top of the inner blue cone.This flame will burn off soot.

Yellow flame from unburned carbon wheninsufficient oxygen.This flame will deposit soot on any cool object.

Larger view of painting

Priestley’s pneumatic trough for collecting gases under water and testing those gases

Lavoisier’s Experiment on Respiration

Photo of Lavoisier’s apparatus

German book about Lavoisier

Lavoisier in his lab