Electrolysis of Copper Sulphate

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Electrolysis of Copper Sulphate

By Ali Hlaiyil

Introduction/Initial Research:

Electrolysis is the production of useful elements as compounds by using electrical energy and converting it into chemical energy.

The reaction takes place when electricity is passed through a circuit, which at one point is split by 2 electrodes, which are dipped into a solution called the electrolyte. The electrodes must be made of a conductive metal, that wither needs to be plated, or is needed in the production of Hydrogen, or other gases.

The electrolyte which is a compound solution made up of many elements, is split up into individual elements or even small compounds when the electricity is turned on and passed through the electrodes and into the water. When this happens, the positive ions move towards the negative anode, and the negative ions in the mixture move to the now positive cathode.

At the cathode an element is collected, and usual plates the electrode, the thickness of the plating being determined by the power of the current and the length of time that the electrolysis reaction goes on for.

At the anode however, gas is usually collected, and is passed into the surrounding air.

In my experiment I have chosen the copper sulphate solution to electrolyze.

In the experiment when the solution is being electrolyzed it starts to decompose and at the positive cathode copper is formed, and makes a thin plating around it. At the anode however, oxygen is formed, and is released.

This comes about because of the chemical change that has happened, as a result of the electricity being passed through and disrupting the ions, making them mix and collect at different electrodes depending on the polarity of the ions.

At the cathode the copper ions become atoms and form on it, creating thin plating, this is the reaction that takes place there…

Cu2+ + 2e- Cu

At the anode, the copper decomposes forming copper ions; this is the reaction that takes place…

Cu Cu2+ - 2e-

As a result of this, the anode is worn away as the copper is decomposed, and oxygen is formed, while at the cathode mass is gained because copper is formed on it and creates plating.

When the copper anode decomposes it loses 2 electrons and copper ions, which have a positive charge. The copper sulphate solution then decomposes the copper ions from the anode, and they go into the solution, making them leave the copper sulphate solution.

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Copper ions then move towards the cathode, which has a negative charge. At the cathode the copper ions each receive 2 electrons and become copper atoms:

Cu2+ + 2e- Cu

The copper atoms collect together on the cathode, which results in it gaining weight. At the anode the hydroxide ions in the solution are also decomposed and go to the anode. They each give up 4 electrons to become oxygen and water atoms in the solution:

4OH – 2H2O + O2 + 4e-

The oxygen bubbles off and is released as gas. The diagram below shows a more ...

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