John Dalton: Difference between revisions
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'''John Dalton''' (1766-1844) was an [[English people|English]] scientist. He taught [[mathematics]] and [[physical sciences]] at New College, Manchester. Dalton revived the atomic theory of [[matter]], which he applied to a table of atomic weights and used in developing his law of partial pressures ([[Dalton's law]]). He was [[color-blind]] and studied that affliction, also known as Daltonism. | '''John Dalton''' (1766-1844) was an [[English people|English]] scientist. He taught [[mathematics]] and [[physical sciences]] at New College, Manchester. Dalton revived the atomic theory of [[matter]], which he applied to a table of atomic weights and used in developing his law of partial pressures ([[Dalton's law]]). He was [[color-blind]] and studied that affliction, also known as Daltonism. | ||
Another important achievement of Dalton's was his law of ''multiple proportions'': If two [[elements]] form more than one compound, the weights in different compounds of an element are in integral ratio to each other. For instance, consider the elements [[nitrogen]] and [[oxygen]]. The element oxygen occurs in the compounds NO and NO<sub>2</sub>. The ratio of oxygen weights in these compounds is the integral number 2. (Note that in modern chemistry the concept "weight", used by Dalton, is replaced by "number of atoms". Now we say that the ratio of numbers of O-atoms in different NO<sub>x</sub> compounds is an integral number. Or, by extension of Dalton's law of multiple proportions, the subscripts m, n, k, ... in a compound A<sub>m</sub>B<sub>n</sub>C<sub>k</sub>⋅⋅⋅ are integral numbers.) This law led Dalton to take the mass of the lightest element, [[hydrogen]], as unit of [[atomic mass]]. | |||
Revision as of 06:43, 5 December 2007
John Dalton (1766-1844) was an English scientist. He taught mathematics and physical sciences at New College, Manchester. Dalton revived the atomic theory of matter, which he applied to a table of atomic weights and used in developing his law of partial pressures (Dalton's law). He was color-blind and studied that affliction, also known as Daltonism.
Another important achievement of Dalton's was his law of multiple proportions: If two elements form more than one compound, the weights in different compounds of an element are in integral ratio to each other. For instance, consider the elements nitrogen and oxygen. The element oxygen occurs in the compounds NO and NO2. The ratio of oxygen weights in these compounds is the integral number 2. (Note that in modern chemistry the concept "weight", used by Dalton, is replaced by "number of atoms". Now we say that the ratio of numbers of O-atoms in different NOx compounds is an integral number. Or, by extension of Dalton's law of multiple proportions, the subscripts m, n, k, ... in a compound AmBnCk⋅⋅⋅ are integral numbers.) This law led Dalton to take the mass of the lightest element, hydrogen, as unit of atomic mass.