Transformation of chemical energy to electric
Transformation of chemical energy to electric is connected with the phenomenon of electrolytic dissociation which essence consists in formation of the charged particles — ions at dissolution of nekoyotory substances (acids, salts, etc.).
In fig. 1 the zinc plate lowered in water sulphuric acid solution (electrolyte) is shown. Zinc is dissolved in the elektroyolita, and pass poloyozhitelny ions of Zn+ into solution. Solution заряжается it is positive, and zinc — otritsatelyyono. Dissolution of zinc is caused
by chemical forces.
In the field of contact zinc — solution appears the electric field of the formed ions directed from the rastyovor to zinc.
In process of dissolution of zinc the charge, and together with it and electric field intensity grows. Electric ate counteracts transition of ions of Zn + in solution therefore on the certain stayodiya dissolution of zinc stops.
Such equilibrium state corresponds to equality of two forces operating on Zn+ ions: chemical under the influence of which zinc is dissolved, and electric, interfering dissolution. Rastyovoreniye of zinc stops in the presence of some difference of potenyotsial? 1 between zinc and solution.
If to place the plate from other substance in the same solution, then the described process will take place and in this case. But poluchenyony potential difference? Can be 2 other size — more or less? 1.
By such principle it is formed э. of page of the galvanic cell and accumulator (fig. 2 and, b).
At connection of plates by I and II conductors in the closed circuit will work э. of page of chemical element
Ea =? 1 —? 2,
also electric current will be established.
In this case э. of page is created and supported during the work of the element with chemical forces (third-party forces), and, therefore, it is possible to speak about transformation of chemical energy to electric.
Electric current in the galvaniyochesky element is followed by irreversible electrochemical processes which can be opiyosat certain chemical reactions.
Application of galvanic cells is limited — in unit of time they can give only neznayochitelny amount of elektricheyosky energy, and the term of their work is small and comes to an end when active agent of electrodes to some extent is izrasyokhodovano.
Considerably bigger primeneyony have accumulators which elektroyokhimichesky processes of the obyoratima. The reversibility of elektrokhimiyochesky processes allows to provoyodit repeated charging and the razyoryadka of accumulators. At charging in them the certain amount of chemical energy at the expense of the spent electrical energy collects, and when discharging this energy can be used in the electric circuit in the form of elekyotrichesky energy.Top