Lecture #1

  CURMUDGEON GENERAL'S WARNING. These "slides" represent highlights from lecture and are neither complete nor meant to replace lecture. It is advised not to use these as a reliable means to replace missed lecture material. Do so at risk to healthy academic performance in 09-105.
Lecture Outline History

The first 2000 years

Stoichiometry Laws

Conservation of Mass

Law of Definite Proportions

Law of Multiple Proportions

Law of Combining Volumes

Avogadro's Law

A quick history of the development of chemistry as a science starts in ~-400 BC.
Measurements led to one of the important early laws of chemistry, the Law of Conservation of Mass. The text, p. 17, expresses this as in every chemical operation "mass is neither created nor destroyed."
Some chemical discoveries in the early 1800s.
Experimental measurements led to the second important early observation, the Law of Definite Proportions. The text, p. 17, expresses this Law as "a given compound always contains exactly the same proportion of elements by mass."
John Dalton observed a pattern in results of chemical analysis on compounds (substances made from two or more elements) made from the same elements. For example, carbon and oxygen can produce carbon dioxide and carbon monoxide. From analyses of their composition by weight and similar analyses on other sets of compounds, he produced the "Law of Multiple Proportions". On p. 18, it reads as "When two elements form a series of compounds, the rations of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers."
This is a numerical illustration (not done during lecture) of Dalton's Law of Multiple Proportions showing how "small whole numbers" emerge.
John Dalton and his 1803 Theory of Atomic Theory of Matter. The last postulate is referred to as the "Postulate of Simplicity."
Dalton's Theory has some crucial faults.
 The French scientist, Gay-Lussac, studied reactions of gases all at the same temperature and pressure and noted a pattern involving the gas volumes.  
Gay-Lussac's study of combining volumes of gases provides a clue
Avogadro accepts the significance of Gay-Lussac's experiments and hypothesizes some significant ideas.