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Factors that might affect the mass of metal deposited during…
Factors that might affect the mass of metal deposited during electroplating?
Temperature of copper sulfate
Research
Improvements in plating efficiency as temperature increases
The resistance of electrolyte solution and cell is reduced with the rise in temperature leading to an increased rate of electrodeposition of copper.
As temperature increases, kinetic energy increases. Ultimately increasing collsion rate therefore, increase in rate of reaction and possible increase of plating on cathode
Decision
This factor will not be measeured and the experiment will be conducted under room temperature due to the difficulty to maintain the temperature and the danger high temperature would have on the investigators
Advantages/Disadvantages
Maintaining a constant temperature requires high supervision and maintainence.
High temperature could be dangerous to maintain and extra precausions would be required to maintain the temperature
Although low temperature is less dangerous than high temperature, it is still difficult to maintain the temperature and cooling systems would be required to do so
pH of the Copper sulfate
Advantages/Disadvantages
Difficult to calculate the appropriate amount of acid and base solution to achieve the appropriate pH
Difficult to identify if the copper sulfate is at its appropriate pH
Research
If the pH of the solution is very high, metal hydroxides such as CuOH form and begin precipitating out of the solution, reducing the efficiency of the electrolysis process
If the pH of the solution is too low, particles of H+, or protons, also will be deposited onto the metal
Decision
This factor will be measured and will be kept at a constant pH as it is difficult to control by calculating the appropriate volume of acidic and basic solution to add into the copper sulfate solution.
Voltage of the circuit
Advantages/Disadvantages
It is easy to maintain the voltage by using a dial on a power pack
Due to material limitations, there may not be enough power supplies to run all of your trials at the same time, reducing the amount of time each experiment can be run and increasing the impact of random error.
Research
Voltage is directly proportional to current and inversely proportional to circuit resistance, according to Ohms Law.
Because the quantity of charge in a circuit is directly proportional to the current, The charge will increase as the current increases.
The chemical deposition caused by the flow of current through an electrolyte is directly proportional to the quantity of charge, according to Faraday's First Laws of Electrolysis.
As a result, increasing the voltage will theoretically increase the mass of metal deposited on the cathode.
Decision
The voltage of the circuit will be the independent variable as the factor is easy to alter by turning the dial on the electrolytic cell
Duration of electroplating
Advantages/Disadvantages
This factor is easy to control by using a stop watch and monitoring it
Decision
As the duration of electrolysis affects the mass of copper deposited, this factor will have to be controlled.
Research
As the duration of electrolysis increases, the mass of copper deposited would also increase. This is because more time is provided for the copper to deposit the ions to the cathode
Surface area of electrodes
Advantages/Disadvantages
Easy to maintain for experiments
Measuring the surface area of a cathod can be challenging
It is difficult to aquire cathodes of different surface areas and ones which have surface areas which compare in a linear fashion
Research
The area on the electrodes increases as the surface area increases. As a result, there will be more contact between the solution and the electrodes. According to collision theory, when more collisions occur per unit of time, the rate of reaction will grow.
Decision
Surface area is decided not as a independent variable as it increases the chance for errors. Results would also be difficult to compare due to a lack of unchronological increase in surface area which leads to interpolation imparing the accuracy of the results
Safety consideration
Copper sulfate
Copper sulfate is a severe eye irritant and can cause substantial damage to the eyes.
Copper sulfate should not be ingested. Doing so will cause serious diarrhea and vomiting
If inhaled, the dust can cause respiratory irritation.
Additional considerations
Sample size
Longer duration of electrolysis increases the precision of the result by reducing random error
Variables
Dependent variable
Rate of copper decomposition on the electrode
Independent variable
Voltage of the circuit
Determining the mass of metal deposited
The mass of any element deposited during electrolysis is directly proportional to the number of coulombs of electricity passed
The mass of an element deposited by one Faraday of electricity is equalivant to the atomic mass in grams of the element divided by the number of electrons required to reduce one ion of the element to its metal.
Measure the cathode before the experient and measure it after the experiment. Mass of copper deposited = Mass of cathode after experiment - Mass of cathode before experiment.
Distance of electrodes
Advantages/Disadvantages
it is difficult to maintain the distance of the electrodes for experiment
The investigators would have to pay close attetion to the distance of the electrodes and ensure that they maintain the appropriate distance
Research
Deposition effeciency increased when electrode distance were decreased
The internal resistance of a battery cell increases with an increase in distance between two electrodes.
Decision
As the distance of electrodes does affect the rate of deposition it would have to be a controlled variable, if this factor is not controlled, the accuracy and validity of the results would be impaired. This factor will be controlled by placing the electrodes at the opposite ends of the electrolytic cells
Concentration of Copper Sulfate
Advantages /Disadvantages
Concentration is easy to alter by dilution using water or dissolving more solute in the solution
Research
Higher concentration of copper sulfate increases the rate of electrolysis
Higher concentration of copper sulfate increases the current
Lower concentration of copper sulfate decreases the rate of electrolysis
Decision
This factor will not be measured and the concentration the copper sulfate will be 1.0M