Ampere-second

By contrast, in SI units, the coulomb (C) is the unit of charge and is defined as an ampere second (A sec). To reconcile this with newtons and meters, the units of F and r, respectively, a proportionality constant that is numerically different from unity and which has definite units is required. For charges under vacuum we write... 

The thin-layer configuration and its associated diffusion problems means that it is possible to oxidise (or reduce) all of the electroactive species in the thin layer before they can be replenished to any marked degree. Consider, for example, the 0"+/0 couple, with a standard redox potential well within the "electrochemical window of the solvent, so that the current in the absence of the couple is small and can easily be accounted for. With the electrode pushed against the window the potential is stepped cathodic enough to ensure the rapid reduction of the 0" + and the current measured as a function of time, the concentration such that the time for the current to reach zero, or a steady residual value, is small. If the area under the I ft curve is A ampere seconds, then the charge passed Q = A coulombs. Thus, the number of moles of 0"+ reduced, N0, is given by ... 

One coulomb C or one ampere-second is a unit of quantity of electricity (electric charge) required to deposit 0,001118 grams of silver from a solution of silver nitrate regardless of the time during which the current passed through the electrolytic cell. This definition means that a current of one ampere represents a quantity of electricity equivalent to one coulomb per second. 

Combination of the mechanical system with electric phenomena requires an additional base quantity of an electrical nature. As such the Ampere has been chosen as basic unit. The derived unit of electrical energy, the Joule (= Volt Ampere second = Watt second) is equal to and identical with the unit of mechanical energy, the N m ... 

What unit is equivalent to the each of the following combinations of units (a) ampere-second,... 

Hence 1 mole of electrons passing through the cell would produce 1 mole of sodium atoms. One mole of electrons is 1 faraday, and 1 mole of sodium atoms is a gram-atom of sodium, 23.00 g. Hence the amount of electricity required is 96,500 coulombs, 1 faraday. One coulomb is 1 ampere second. Hence 96,500 coulombs of electricity passes through the cell if 1 ampere flows for 96,500 seconds, of 20 amperes for 96,500/20 = 4825 sec., or 1 hour 20 min. 25 sec. 

One coulomb is the amount of charge that passes a point when a one-ampere current flows for one second (1 coulomb = 1 ampere-second). Thus, a current of 96,500 amps flowing for one second contains Avogadro s number of electrons, or one faraday of charge. 

Figure 7-24 Slope Compensation Can Be Expressed Either in Terms of Amperes/Second or as Volts/Second, through the Use of the Transfer Resistance...

Amperage limitation, current cycling, or intermittent current application lengthens the required coating time, since it is the applied ampere seconds (Coulombs) that produce the electrodeposit. 

In modern language this states that the quantity of electricity required to make one mole of an electrode product is a universal constant multiplied by the number of electrons required per molecule (or per ion), the constant is the Faraday (symbol F) with a value of 96485 coulombs or 96485 ampere seconds. It could be expressed ... 

Electric potential difference Volt V joule/ (ampere) (second) J/(As)... 

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