Arthur Amos Noyes
Encyclopedia
Arthur Amos Noyes was a U.S. chemist
and educator. He served as the acting president of MIT between 1907 and 1909. He received a PhD. in 1890 at Leipzig
under the guidance of Wilhelm Ostwald
. Roscoe Gilkey Dickinson
was one of his famous students. Noyes served as Professor of Chemistry at the California Institute of Technology
from 1919 to 1936. He was a major influence on the educational philosophy and the core curriculum of Caltech. He also served on the board of trustees for Science Service, now known as Society for Science & the Public
, between 1921 and 1927.
, he formulated the Noyes-Whitney equation
in 1897, which relates the rate
of dissolution
of solid
s to the properties of the solid and the dissolution medium
. It is an important equation in pharmaceutical science
. The relation is given by:
Where:
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
and educator. He served as the acting president of MIT between 1907 and 1909. He received a PhD. in 1890 at Leipzig
Leipzig
Leipzig Leipzig has always been a trade city, situated during the time of the Holy Roman Empire at the intersection of the Via Regia and Via Imperii, two important trade routes. At one time, Leipzig was one of the major European centres of learning and culture in fields such as music and publishing...
under the guidance of Wilhelm Ostwald
Wilhelm Ostwald
Friedrich Wilhelm Ostwald was a Baltic German chemist. He received the Nobel Prize in Chemistry in 1909 for his work on catalysis, chemical equilibria and reaction velocities...
. Roscoe Gilkey Dickinson
Roscoe G. Dickinson
Roscoe Gilkey Dickinson was a U.S. chemist, known primarily for his work on X-ray crystallography. As professor of chemistry at the California Institute of Technology , he was the doctoral advisor of Nobel laureate Linus Pauling and of Arnold O...
was one of his famous students. Noyes served as Professor of Chemistry at the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
from 1919 to 1936. He was a major influence on the educational philosophy and the core curriculum of Caltech. He also served on the board of trustees for Science Service, now known as Society for Science & the Public
Society for Science & the Public
Society for Science & the Public , formerly known as Science Service, is a 5013 non-profit organization dedicated to the promotion of science, through its science education programs and publications, including the weekly Science News magazine.Headquartered in Washington, D.C., the organization...
, between 1921 and 1927.
Noyes–Whitney equation
Along with Willis Rodney WhitneyWillis Rodney Whitney
Willis Rodney Whitney was an American chemist and founder of the research laboratory of the General Electric Company.- Early life and studies :...
, he formulated the Noyes-Whitney equation
Equation
An equation is a mathematical statement that asserts the equality of two expressions. In modern notation, this is written by placing the expressions on either side of an equals sign , for examplex + 3 = 5\,asserts that x+3 is equal to 5...
in 1897, which relates the rate
Rate
In mathematics, a rate is a ratio between two measurements, often with different units. If the unit or quantity in respect of which something is changing is not specified, usually the rate is per unit time. However, a rate of change can be specified per unit time, or per unit of length or mass or...
of dissolution
Solvation
Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute...
of solid
Solid
Solid is one of the three classical states of matter . It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a...
s to the properties of the solid and the dissolution medium
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
. It is an important equation in pharmaceutical science
Pharmacy
Pharmacy is the health profession that links the health sciences with the chemical sciences and it is charged with ensuring the safe and effective use of pharmaceutical drugs...
. The relation is given by:
Where:
is the rate of dissolution.- A is the surface areaSurface areaSurface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved than the definition of arc length of a curve. For polyhedra the surface area is the sum of the areas of its faces...
of the solid. - C is the concentration of the solid in the bulk dissolution medium.
is the concentration of the solid in the diffusionDiffusionMolecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
layer surrounding the solid.- D is the diffusion coefficientCoefficientIn mathematics, a coefficient is a multiplicative factor in some term of an expression ; it is usually a number, but in any case does not involve any variables of the expression...
. - L is the diffusion layer thickness.