Kinetics Before 1900

By Angie Gonzalez, Eaindar Soe, Izabela Gowranska, Schalyn Bogart

Kinetics is the branch of classical mechanics that concerns the effect of forces and torques on the motion of bodies having mass. Chemical kinetics, also known as reaction kinetics, is the study of rates of chemical processes. Since mid 20th century, scientists prefer to say “analytical dynamics” or simply “dynamics. There are a lot of scientists of most contributions to the development of chemical kinetics, particularly in early years.

OUTLINE

I. Rates of Chemical Reactions

1. Wenzel (1740-1793)

1777: Rates of dissolution of metals in acids

2. Thenard (1777-1857)

1818: Rates of decomposition of hydrogen peroxide

3. Wilhelmy (1812-1864)

1850: Rates of inversion of sucrose; (hydrolysis into D (+) glucose and D (-) fructose in the presence of an acid) and found it to be proportional to the concentrations of both the sugar and the acid.

4. Harcourt (1834-1919) & Esson (1839-1916)

1865: Studies the dependence of rates of reaction on the concentration of the reactants

5. Van’t Hoff (1852-1911)

1884: Introduced equilibrium to express the dynamic nature of chemical systems & systematized chemical reactions (orders of reactions = molecularity). 6. Friedrich W. Ostwald (1853-1932)

1887: He defined the order of reaction which was previously introduced by Van’t Hoff who called it, molecularity.

II. Chemical Equilibrium (then “Chemical Dynamics”)

1. Saint-Gilles and Berthelot (1827-1907)

1863: Studies the reaction: alcohol + acid = ester + water which slowly and progressively approach a limit corresponding with equilibrium.

Conclude mathematical expression for the velocity of reaction.

2. Gulberg (1836-1902) & Waage (1833-1900)

1864: Develop the law of mass action in three stages; formulated their "law of mass action," according to which the reaction "forces" are proportional to the product of the concentrations of the reactants

3. Horstman (1854-1929)

1871: Applied Clausius-Clapeyron’s thermodynamics equation showed that at equilibrium entropy is at maximum. (First to apply concepts from classical thermodynamics to study chemical systems).

4. Van’t Hoff (1852-1911)

1884: Published a book including possible equations relating rate constants to temperature dependence of equilibrium constants.

III. Electrochemistry

1. Humphry Davy (1778-1829)

1813: Discovered the volatie pie to lay the qualitative foundations of

Electrochemistry.

2. Michael Faraday (1791-1867) 1834: Formulated the first and second laws of electrochemistry.

3. Friedrich W. Ostwald (1853-1932)

1884 -1887: Contribute the theory of electrolytic solutions with Arrhenius together.

4. Svante Arrhenius (1859-1927)

1884: Hypothesis of Williamson and Clausius by suggesting that electrolytic part must be capable of double decomposition

Degree of ionization calculated from the electrical conductivity where the equivalent conductivity at infinite dilution is (when there is complete ionization).

1889: Pointed out that molecules need to collide with a minimum energy; further analyzed the temperature dependence of reaction rate, k = an exp (-B/T), and gave it an "energy barrier" interpretation.

References:

King, M. C. Ambix 1981, 28, 70-82.

King, M. C. Ambix 1981, 29, 49-61.

Laidler, K. J. Chemical Kinetics, Harper & Row, New York, 1987.

Laidler, K. J. Chemical Kinetics and the Origins of Physical Chemistry, University Of Ottawa, 1984.

Partington, J. R. A Short History of Chemistry; Macmillan & Co. Ltd, New York, 1957.

Partington, J. R. History of Chemistry, Robert Maclehose And Co. Ltd, Glasgow, 1963.