Electrolysis of Copper in Copper Sulphate Solution

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Electrolysis of Copper in Copper Sulphate Solution

Introduction

Aim

This is an investigation into how temperature affects the amount of

copper lost from the Anode and gained on the Cathode during

electrolysis.

Electrolysis is…

The chemical change by passing electric charge through certain

conducting liquids (electrolytes). The current is conducted by

migration of ions - negative ones from the Anode (positive electrode),

and positive ones to the Cathode (negative electrode). Reactions take

place at the electrodes by transfer of electrons in the direction of

the current.

In this case, copper electrodes in a copper sulphate solution are

used.

In the electrolysis of copper, copper atoms in the Anode become copper

ions by losing electrons which go into the circuit.

Cu - 2e à Cu

The positive ions are attracted to the negative Cathode but only

copper ions are discharged.

Cu - 2e à Cu

So this electrode gets coated with copper.

Diagram

[IMAGE]

Also attached to this circuit will be a variable resistor. An ammeter,

placed in the circuit, will register the flow of current: from this

indication, the electric circuit can be deduced to be complete.Also, a

stopwatch will be used.

The 'cell' is a power pack.

Variables

The variables in this experiment are:

· The electrodes

· Resistance

· The electrolyte

· Temperature

· Position of the electrodes (Distance between)

· Time

Only the size of the electrodes and times are being investigated,

therefore in order for this to be a fair test, the other factors must

be kept constant.

The same CuSO will be used throughout, so the concentration is the

same, and the same spacing between electrodes will be used. The size

of the electrodes should be the same, but they will be reused, so the

size will change from one experiment to another.

Time intervals of 5 minutes for each experiment will be used, until it

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