SU1640735A1 - Process for determination electrolysis parameters - Google Patents

Abstract

The invention relates to methods for conducting laboratory work in physics, in particular in the course on electricity. The purpose of the invention is to improve the accuracy and simplify the process of measuring the mass of the substance released at the cathode. The method involves measuring using the weights of the mass of the cathode before and after passing an electric current through the electrolyte, the cathode being made of the same material as that released during electrolysis, and the mass of the cathode TC is measured with its full immersion in the electrolyte according to the formula HPA (р к / Я к {b) mr- where р к and рз are the densities of the cathode and electrolyte materials, respectively, mr is the mass of weights on the scale pan. 1 silt

Description

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The invention relates to methods for conducting laboratory work in physics and can be used in universities and secondary schools in the course of studying the effects of electrolysis in the course of electricity.

The purpose of the invention is to improve the accuracy and simplify the process of measuring the mass of the substance released at the cathode.

The essence of the method is that when determining the parameters of electrolysis by measuring the mass of a substance released on the cathode, which includes measuring with the weight of the mass of the cathode before and after passing an electric current through the electrolyte, the mass of the cathode is measured with its full immersion in the electrolyte

GPK -mr,

RK- / OE where t is the mass of the cathode;

/ OK - density of the cathode material;

re is the electrolyte density;

mr is the weight reading (the weight of the weights on the weighing pan), while the cathode is made of the same material as that released on it during electrolysis.

The drawing shows the implementation of the proposed method.

The mass of the cathode 2 immersed in the electrolyte 1 is measured using lever weights 3, the cathode 2 is attached to the right rocker and the cup 4 with weights 5 is attached to the left rocker arm. The electrical voltage to the cathode 2 is supplied through the metal suspension 6 and removable pin 7.

To derive a formula for calculating the mass of an electrode immersed in an electrolyte solution, we use the equilibrium conditions of the balance beam balance. If right and

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the left suspension and the balance cups are the same, and the arms of the rocker have the same length, then the arrow of the eight weights is in the equilibrium position under the condition of equality, the tension forces acting on the right (T) and left (T arms of the rocker arm (due to tension enter the gravity force acting on the scales).

As can be seen from the diagram of the acting forces indicated in the drawing,

T + Gd-tk; (1)

 1+ t g q 0, (2)

where is the FA - buoyancy force; TC is the mass of the cathode;

mr is the mass of weights;

 free fall acceleration. The scaled view of the projection of forces is given by T tkd - FA; (3)

T mrg. (4)

Since the left sides of these equations are equal.

tk g - FA mr g (5)

The buoyancy is determined by the known formula

FA /% gVK (6)

where re - the electrolyte density;

VK is the volume of the submerged part of the cathode (with full immersion, the volume of the entire cathode).

Taking into account that VK tk / p to (7), and, substituting in (6) and (5), we obtain

m to tkd - re q pY mr q.

Solving the resulting equation with respect to TK, we get Pk

tk-

mr

(eight)

Rk-rz

Thus, if the densities of the cathode material and the electrolyte are known, then the cathode weight can be easily determined by the weight of the weights on the scale pan.

According to the cathode masses calculated according to equation (8), the electrochemical equivalent K of deposited material is easily calculated.

Atk Rk Atg I

 -

k. -: - t- (9)

tРк-Рэ I t

where I is the force flowing through the electrolyte current;

t is the time of its passage;

Am k and Amr are the mass gains of the cathode and weights, respectively, during the passage of current through the electrolyte.

The Farad's constant F is found by the formula

n M M It. Pk-p

Z DTG

Rk

(YU)

where M is the molar mass of the substance that is deposited on the cathode; Z is its valence.

Claims (1)

The invention The method of determining the parameters of electrolysis by measuring the mass of a substance released on a cathode, including measuring with the weight of a cathode mass before and after passing an electric current through the electrolyte, characterized in that, in order to improve the accuracy and simplify the measurement process, the cathode is made from the same material as that released during electrolysis, the mass measurement is carried out by hanging the cathode immersed in the electrolyte to the balance using the formula P GPK mr Rk-Rae where mk and mr are the cathode masses real and according to the indications of the weights, respectively; P to and re the density of the material of the cathode and the electrolyte, respectively.