Results 1–6 of 6 for Coulomb%E2%80%99s law
Coulomb’s law is the statement that the force F between two electrical charges q1 and q2 separated by a distance r is
where εo is the permittivity of a vacuum, equal to
Electric dipole moment (μ) is a product of the positive charge and the distance between the charges. Dipole moments are often stated in debyes; The SI unit is the coulomb metre. In a diatomic molecule, such as HCl, the dipole moment is a measure of the polar nature of the bond; i.e. the extent to which the average electron charges are displaced towards one atom (in the case of HCl, the electrons are attracted towards the more electronegative chlorine atom). In a polyatomic molecule, the dipole moment is the vector sum of the dipole moments of the individual bonds. In a symmetrical molecule, such as tetrafluoromethane (CF4) there is no overall dipole moment, although the individual C-F bonds are polar.
Farad (F) is the SI derived unit of electric capacitance. The farad is the capacitance of an electric capacitor between the two plates of which there appears a difference of electric potential of one volt when it is charged by a quantity of electricity equal to one coulomb (F = C/V). The unit was named after the British scientist M. Faraday (1791-1867).
Gauss’ law describes the relation between charge and electric field in static situations, so it is equivalent to Coulomb’s law, which can be derived from Gauss’ law. Gauss’ law states that the net flux of electric field, Φ, through an imaginary closed surface, S, - a Gaussian surface - is equal to the net charge, q, inside that closed surface:
where electric flux Φ through Gaussian surface is given by:
ε0 is the permittivity constant and dS is a surface element.
Silver coulometer consists of a platinum vessel which acts as a cathode and contains a solution of pure silver nitrate as an electrolyte (c(AgNO3) = 1 mol/L). A rod of pure silver enclosed in a porous pot acts as the anode. The current density at the anode should not exceed 0.2 Acm-2. After electrolysis, the electrolyte is taken out and the platinum vessel is washed, dried and weighed. The increase in the weight gives the amount of silver deposited (96500 C of electricity deposits 107.88 g of silver). From the mass of the silver deposited, the coulomb involved in the reaction can be calculated.
Generalic, Eni. "Coulomb%E2%80%99s law." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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