The copper ions move to the cathode and are discharged by gaining electrons, and are deposited on the electrode as metallic copper,
Equation Cu+2 + 2e- ➔Cu (Reduction)
The chloride ions move to the anode and are discharged, by losing electrons, as chlorine gas.
Equation 2Cl-1➔ Cl-1 + 2e- (Oxidation)
Here is a diagram to show the ions going to the electrodes
Hypothesis
I think that in the solution the more electrons flowing the more you have a chance of seeing a better chemical reaction taking place. The more current flowing the quicker the reaction and if the solution is less concentrated then there will be less chlorine gas let of and less copper formed so if we increase the concentration, the more chlorine gas given out and more copper formed.
The changing of the current does matter to the amount of copper being gained because if the current is to less then there will be a really slow reaction. If there is a really high current then there will be a really fast reaction and copper formed will start dripping into the beaker and then we will not be able to weigh that and so we will have to do the experiment again.
On the positive side (anode) there will be chlorine gas going out and on the negative side (cathode) there will be metallic copper on the electrode.
This is what I think will happen
Plan
The apparatus which I need are as follows
- D.C. power supply for the power needed to do this experiment
- Electrodes [Anode (+) and Cathode (-)]
- Thermometer - for measuring the surrounding temperature in order to keep it a fair test.
- Circuit wire - for connecting up the apparatus to the power supply.
- Beaker - for holding copper chloride solution.
- Copper chloride solution - for doing the electrolysis experiment.
What results I will collect: I will fill the beaker with copper chloride solution and set out the experiment while my partner will go and record the weight of the electrode. Then we will do the experiment and wait for 3 minutes and when the reaction is finished after 3 minutes we will go and weigh the electrode. Afterwards we will record the result. To find out how much copper is made we will subtract the weight of the electrode before the experiment from the weight of the electrode after reaction.
I will alter the current every time I do the experiment because then not also can I find out how much copper is formed but also how much because I think that if there is less current, then there will be less copper formed and I want to prove my hypothesis and so if I vary the current I will found out and then prove my predictions.
I will keep the same amount of solution and the same amount of concentration because if I did not it will not be a fair trial. This is because if I don’t keep the same amount then the one with more solution will form more copper and the one with less solution that one will form less copper. If I don’t keep the concentration the same then the one with more concentration will have more ions than the one with less concentration. The more ions you have the more copper will be formed, the more chlorine gas will be let of and the better results you will have.
I think that the positive ions will draw towards the negative electrode and will be covered with metallic copper and the negative ions will attract to the positive electrode and will be let out as chlorine gas.
When we do this experiment there are some safety precautions that we will have to consider
- Electricity is dangerous therefore we have to be careful while connecting the apparatus and while we are connecting the apparatus we have to always check if the power supply is turned off.
* Too much electricity is also dangerous because it might cause the equipment to work over load causing it to break. May be the circuit wire might melt, causing fires.
* And we always have to wear safety goggles.
Diagram
This is a diagram to show how we are going to set it out.
Aim: We are trying to find out what factors affect the rate of electrolysis of copper chloride solution.
Method: We set out the experiment as in the plan above but we made a few modifications. We tried out the experiment timing it for 3 minutes but that was too long because the copper was coming off the electrode and it was going into the solution and so we could not measure the copper that was in the solution. So we decreased the amount of time to 30 seconds. We also repeated the experiment twice so we can find the average amount of copper made.
We are going to use the strongest (less diluted) copper chloride solution and this solution is mixed together to make a solution as follows: every 100g of copper chloride there will be 2 litres of water.
We will use 50 ml of copper chloride solution on every trial experiment we do.
Results
A table to show the results collected.
Conclusion
I have learnt that the more electrons flowing the more chance you have of seeing a better reaction taking place, the more current flowing the quicker and better the reaction and the more concentrated the solution the more electrons will be in the beaker instead of water and the better reaction you will get. If we have a high current then there was more copper formed and more chlorine gas let off in 30 seconds. If we have a low current then there is less copper formed and less chlorine gas let off.
Here is a diagram of what actually happened
Evaluation: My results were reliable and I had enough results to reach to a conclusion. I had some unexpected results on the weight of the electrode before the reaction because we measured the same electrode and there weight was different. If I had more time then I would have changed the solution to a less diluted one.
Overall I carried out a fair trial.
