Chemistry Experiment

Chemistry Experiment

How does the change in the electric current used in

the electrolysis of copper sulphate solution affect the

mass of copper deposited on the copper electrodes?

Aim

---

The aim of this experiment is to find out whether the mass of copper

deposited on copper electrodes during the electrolysis of copper

sulphate solution changes when the current used to electrolyse the

solution is increased.

Hypothesis

----------

I predict that if the current used to electrolyse the copper sulphate

solution is increased, then the mass of copper deposited on the copper

cathode will increase. Also as the current is increased the mass of

the anode will decrease. I also predict that the mass change of the

copper electrodes is directly proportional to the current. This is

because of what happens during electrolysis.

All electrolytes contain ions, positively and negatively charged ions.

In copper sulphate there are positively charged copper ions (Cu2+) and

negatively charged sulphate ions (S2-). When the copper sulphate is a

solid, the ions are held tightly together in a regular lattice, and

they cannot move. However, when they are into a solution, the ions are

freed from their lattice and can move around.

During the electrolysis of copper sulphate solution, the positively

charged copper ions are attracted to the negatively charged cathode,

because opposite charges attract. Because electricity is the flow of

negatively charged electrons, when the copper ions contact the

cathode, they attract electrons from the cathode. The electrons then

cancel out the positive charge of ...

... middle of paper ...

...o be done more accurately, I would have to use

more accurate apparatus, such as a newer ammeter, a balance with more

digits, a more accurate way of controlling the current, maybe with a

computer, and also I could use a thermometer to show the change in

temperature, so that it can be monitered. I also could have kept the

size and separation of the electrodes the same. I also could have made

sure that the crocodile clips were completely out of the electrolyte.

Also I could have taken a much wider range of readings, from 0.05A to

1.00A at smaller intervals, maybe at 0.05A graduations, and I could

have timed for different times, and I could have investigated the

other variables, such as the temperature of the electrolyte, the

concentration of the electrolyte, the separation of he electrodes, and

the size of the electrodes.