Transcript Problems with Dalton’s Theory

Problems with Dalton’s Theory
• Law of Combining
Volumes – 1808
At a given temperature
and pressure the volumes
of gases that react with
one another are in the
ratios of small whole
numbers
http://www.woodrow.org/teachers/chemistry/institutes/1992/
Gay-Lussac.html
Problems with Dalton’s Theory
• Avogadro’s Hypothesis –
1811
Equal volumes of gases
at the same temperature
and pressure have the
same number of
molecules
Confusion in Chemistry!
• Jean Dumas(1800-1884)
“If I were in charge, I would efface the word atom from
science”
• Friedrich August Kekule (1829-1896)
1st International Chemical Congress - 1860
http://webserver.lemoyne.edu/faculty/giunta/karlsruhe.html
• Stanislao Cannizzaro (1826-1910) – atomic mass
determination
• “The atomic hypothesis provides a
convenient form of speech, which
successfully describes many of the facts in a
metaphysical manner.
But the handy way in which the atomic
hypothesis lends itself to the representation
of the characteristic features of a chemical
change falls short of constituting a proof that
atoms have any real existence”
Alexander Smith, Professor of Chemistry,
University of Chicago, 1910
[R.E. Dickerson, H.Gray, G.P. Haight,
Chemical Principles, 3rd ed., 1979]