Electrolysis Investigation :: Papers

Electrolysis Investigation Aim To investigate how voltage affects the amount of a copper (Cu) deposited during electrolysis of copper sulphate solution (CuSO4). Variables ========= TEMPERATURE - Approximately 20ÂÂ ° centigrade.The higher the temperature, the faster the ions move through the solution. Thus, more copper is deposited in the given time period. ELECTROLYTE (CONCENTRATION) - 100g per litre. The denser the solution, the slower the reaction. The slower the reaction, the less copper is deposited in the given time period. VOLTAGE - (Input / Key Variable) 1-5 volts. The higher the voltage, the faster the ions move. The faster ions move, the more copper is deposited in the given time period. TIME - 1 minute. The longer the ions have to move, the more copper is deposited. ELECTRODES (AREA) - 211.2cmÂÂ ³. The larger the electrode, the more copper can be deposited on it and faster. ELECTRODES (DISTANCE APART) - 5cm. The further apart the electrodes, the further the ions have to travel, and so it takes longer for the copper to be deposited and the less copper can be deposited in the given time period. Prediction I predict that the higher the voltage, the faster the ions in the copper sulphate solution will move and so deposit more copper at the cathode in the given time period. If I decrease the voltage less copper will be deposited. Below is some scientific theory to back up my prediction. Scientific Theory Electrolysis is the process of decomposing compounds by electrical energy. An element is produced at each electrode. In my experiment the copper sulphate will start to decompose. At the cathode copper will be formed. Oxygen will be formed at the anode. This causes the anode to wear away while the cathode gains mass. According to Faraday's second law of electrolysis, "The quantity of a substance that is electrolysed is proportional to the quantity of the electricity used." It follows that the speed at which a substance is