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Chemical graph theory is the topology branch of mathematical chemistry which applies graph theory to mathematical modelling of chemical phenomena. [1] The pioneers of chemical graph theory are Alexandru Balaban, Ante Graovac, Iván Gutman, Haruo Hosoya, Milan Randić and Nenad Trinajstić [2] (also Harry Wiener and others). In 1988, it was ...
While this is an error, it can often be assumed to be equal to the traditional μS/cm. Often, by typographic limitations μS/cm is expressed as uS/cm. The conversion of conductivity (in μS/cm) to the total dissolved solids (in mg/kg) depends on the chemical composition of the sample and can vary between 0.54 and 0.96.
The SI unit of velocity is m/s, and the SI unit of electric field is V/m. Therefore the SI unit of mobility is (m/s)/(V/m) = m 2 /(V⋅s). However, mobility is much more commonly expressed in cm 2 /(V⋅s) = 10 −4 m 2 /(V⋅s). Mobility is usually a strong function of material impurities and temperature, and is determined empirically.
The SI unit of molar conductivity is siemens metres squared per mole (S m 2 mol −1). [2] However, values are often quoted in S cm 2 mol −1 . [ 4 ] In these last units, the value of Λ m may be understood as the conductance of a volume of solution between parallel plate electrodes one centimeter apart and of sufficient area so that the ...
When the resistivity of a material has a directional component, the most general definition of resistivity must be used. It starts from the tensor-vector form of Ohm's law, which relates the electric field inside a material to the electric current flow. This equation is completely general, meaning it is valid in all cases, including those ...
For example, the mobility of the sodium ion (Na +) in water at 25 °C is 5.19 × 10 −8 m 2 /(V·s). [1] This means that a sodium ion in an electric field of 1 V/m would have an average drift velocity of 5.19 × 10 −8 m/s. Such values can be obtained from measurements of ionic conductivity in solution.
When charged particles move in electric and magnetic fields the following two laws apply: Lorentz force law: = (+),; Newton's second law of motion: = =; where F is the force applied to the ion, m is the mass of the particle, a is the acceleration, Q is the electric charge, E is the electric field, and v × B is the cross product of the ion's velocity and the magnetic flux density.
The second part of Einstein's theory relates the diffusion constant to physically measurable quantities, such as the mean squared displacement of a particle in a given time interval. This result enables the experimental determination of the Avogadro number and therefore the size of molecules.