The aim of this investigation is to find how the variation in current will affect the mass changes of the copper electrodes in a copper sulphate solution.

Factors affecting Electroplating

• Temperature

   The temperature of the copper sulphate solution will affect the experiment because as the temperature rises, the ions in the copper sulphate solution will gain more and more kinetic energy and this kinetic energy are useful in a reaction. If there is more kinetic energy it means that the ions will be moving at a faster rate and when the ions collide, the higher the number of successful collisions will take place.

• Time

   The time shall affect the investigation due to the fact that as the time passes the reaction develops further. As the reaction develops further it causes a greater deposit of mass on the cathode in the copper sulphate solution. This factor needs to be kept constant as there can only one varying factor in the investigation and this factor is not time.

• Molarity /concentration Of Copper Sulphate

   The molarity of the copper sulphate solution would affect the experiment because if the concentration of the solution is that of a quite high number, it may be perceived that the solution would therefore contain a greater number of ions. If the solution contains a greater number of ions it shall affect the experiment because as there are more ions the collision rate will increase and so to would the number of successful collisions.

• Size of electrode (surface area)

The size of the electrode will affect the experiment because it defines the amount of copper particles which are present and are able to take part in the

• Current

• Distance between electrodes

• Volume of solution

• The voltage of the battery

Preliminary experiment

   In the preliminary experiment it was found that the first problem was that of the resistor because first of all sum of the resistors did not even work. The second problem was that the battery, which was provided, was not always the same one, which was used week in and week out. Another problem was the amount of time that that was given         

Prediction

   From my own scientific knowledge and evidence that I have researched it can be predicted that there will be a direct proportionality between time, current flows and the mass deposited on the Cathode (negative electrode). In this I can therefore expect that the charge will double along with the mass deposited if the time of the experiment is doubled.                 

Fair testing

In order to carry this investigation out fairly there are various procedures, which need to be constant. This is to ensure that the results achieved are accurate and none of them can be contested. The first part of making an investigation fair is to ensure that at any given time in the experiment there is only one variable that is being altered. I f there is more than one variable being altered it means that the result of that test can therefore be disclaimed. For instance if the investigation was carried out however not only was there a variation in the current but also a variation in the concentration of the copper sulphate solution. There fore in order this investigation to be a fair one only one of the variables must be changed in the duration of the experiment at all times and that is the current.  

Safety

   In this experiment there are a lot of safety precautions, which need to be taken into consideration. In the first instance in the experiment, which is being carried out electricity, is used. In order to ensure that correct safety regulations are met various step must be taken, in this when handling the battery to ensure that none of the two springs come into bodily contact.          

Apparatus

In this investigation the following equipment shall be required:

Rheostat

6 Volt Batter Pack

Ammeter

Copper Sulphate Solution 0.5M

Wires

Crocodile Clips

Stop Clock

Two copper electrodes

50 cm        ³

Accuracy

In order for accuracy to be gained in this experiment, for each voltage there were 2 sets of readings to ensure that an average could be taken and this average would then be plotted on graph.

Detailed Method

1. Weight the copper anodes in order for the
2. The positive of the terminal was connected to the power pack and the positive terminal of the ammeter was connected in series with the circuit.
3. The positive terminal of the power pack was connected to the negative terminal of the Rheostat.
4. The negative terminal of the Rheostat was then connected to the negative terminal of the ammeter and this allows for the current to be set.

Conclusion

 In conclusion to this experiment it was found that

Evaluation

   As this investigation was carried out it was seen that it could be deemed a conclusive experiment as the evidence gained supported the prediction. Although the investigation was a success there are various aspects of it, which could have been improved vastly. The first factor that proved to be a problem in the experiment is the fact that after each experiment was carried out even though the electrodes were cleaned with alcohol it was noticed that there was still stain on the electrodes so this meant that the experiment would still b a bit less accurate. In order to overcome this problem if the investigation is carried out in future a different pair of electrodes would be used each time an experiment was conducted. Another reason why the experiment could have been a bit altered to gain more accuracy in the investigation is the copper sulphate solution. This could have caused the results to be inaccurate because the molarity and the amount of the solution could be altered from experiment to experiment. To ensure this would not be a problem there should have been a ready prepared batch of copper sulphate solution and this solution should be used after each test. Another factor that could have affected the outcome of the experiment is the differentiation in apparatus. Each time the experiment was carried out it was carried out in a different lab and often students were not able to use the same equipment. If the same equipment was not used this could have contested the results because firstly it would mean that maybe the resistance of the rheostat could be different. Also the investigation was not carried out on the same day and there could be a variation in the whole settings of the experiment. Also the investigation was not even carried out in the same room.

Another factor which may have affected the overall outcome of the investigation, may have been the fact that the practical work of the investigation was carried over from lesson to lesson, meaning that variables such as the concentration or the amount of the Copper Sulphate solution could have changed between lessons. To overcome this problem, a stock solution of Copper Sulphate should have been made so as the concentration remained the same at all times. The same electrodes and equipment should have been used throughout. Also, when weighing, the same electrical balance should have been used as there may have been slight differences between the two balances. This is what could explain the anomaly ("freak" result) in the graph.

I found this investigation very interesting and am looking forward to investigating more of the variables in this experiment, which may or may not affect the mass of copper deposited onto the cathode, such as changing the Current or Temperature variable.

Results

These are the results that I acquired after the duration of the investigation.

The 1st readings gained from the Anode

2nd Reading

Average Mass Lost at Anode

The 1st readings gained from the Cathode

2nd readings

Average Mass Lost at Anode

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