“ Leaves That Are Green” written by Paul Simon performed 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 long Time 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 night Like 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 away And 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.
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”)
Origin of the Pneumatic Trough to 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 (NH 3 , HCl, H 2 S, 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.
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
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 exist and can be made by heating I 2 with Cl 2 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.
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, SiO 2 )
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.
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.
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”
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.
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 when insufficient oxygen. This flame will deposit soot on any cool object.