The Factors that Affect the Mass of Copper

The Factors that Affect the Mass of Copper

Background Information

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Electrolysis is the decomposition of a molten or aqueous compound by

electricity. Electrolysis occurs only in liquids called electrolytes.

Electrolytes are compounds, which conduct electricity when molten or

dissolved in water, but not when they are in a solid state as the

oppositely charged ions are held together by strong ionic bonds in a

giant lattice and this means electricity cannot pass through it and

the ions are unable to move.

If electrolytes are molten or dissolved in water their ions are free

to move, and the movement of ions in liquids is key in electrolysis.

Electrolysis takes place in an electrolyte cell.

The diagram below shows the apparatus used in the electrolysis of

molten or aqueous ionic compounds.

The electrodes (anode and cathode) are known as conducting rods.

Normally they are made out of platinum or graphite as these substances

are chemically unreactive and will not interfere with the experiment.

They are inert electrodes. However in this experiment we are using

copper electrodes. Copper electrodes are active electrodes and these

metal electrodes take part in electrolysis. Copper electrodes are used

in industry to obtain pure copper.

The anode is the positive electrode, electrons flow from the anode to

the battery. The anions, which are negatively charged non-metal ions

(except for some complex transition metal ions) are attracted to the

anode.

The cathode is the negative electrode. Electrons flow into the cathode

from the battery. The cations, which are positively charged metal ions

(except f...

... middle of paper ...

...ted because the longer the time for the

current to pass around the circuit, the greater the amount of time for

the atoms to lose electrons (oxidation) become ions at the anode, and

the greater the amount of time for the ions to gain electrons

(reduction) and form atoms at the cathode. As we know from

investigating current the mass of copper lost at the anode equals that

gained at the cathode, so it can be said if you double the time you

double the amount of copper deposited. Also I predict that the amount

of copper deposited will be directly proportional to the time. It can

be seem from this that I expect the greatest amount of copper

deposited on the cathode to occur when using a time period of 50

minutes, and I expect the least amount of copper deposited on the

cathode to occur when using a time period of 10 minutes.