• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Faraday's Constant

Extracts from this document...


Determining Faraday's Constant by Electrolysis of Copper (II) Sulphate Aim: To find the value of the Faraday constant - the electric charge carried by one mole of electrons - from the electrolysis of aqueous copper(II) sulfate solution, using weighed copper electrodes. Faraday's Law: The amount of substance consumed or produced at one of the electrodes in an electrolytic cell is directly proportional to the amount of electricity that passes through the cell. By definition, one coulomb (C) of charge is transferred when a one-ampere (amp) current flows for one second (s): Introduction: 1) Excess aqueous 1.0M copper (II) sulphate solution will be electrolysed with copper electrodes. 2) Oxidation will occur at the anode, and reduction cathode: Faraday's Constant can be determined through electrolysis by using the increase in mass of the cathode and the charge in the circuit to calculate the total number of electrons that contributed towards the reduction of the copper ions. One mole of these electrons carries one Faraday of charge. The following formula can be used to work out Faraday's constant: F = Faraday's Constant I = current (amps) t = time (seconds) M = molar mass of copper (63.55) ...read more.


Time Change in Mass of Cathode seconds grams �1.00 s �0.002g 0 0.000 300 0.050 600 0.087 900 0.117 1200 0.158 1500 0.190 1800 0.230 2100 0.270 2400 0.290 2700 0.326 Uncertainties: Instrument Error of Instrument Error Calculation Error (%) Electronic Balance �0.001 grams (0.002/0.191) x 100 1.05 Voltmeter �0.01 Volts (0.05/0.6) x 100 8.33 Stop clock (human error) �2.0 seconds (2.0/300) x 100 0.67 Ammeter �0.01 Amps (0.01/0.35) x 100 2.86 Total Uncertainties affecting Results = 4.58% (the voltmeter error does not affect result, as it is not a component in the equation being used) Gradient: The gradient can be calculated from the graph. I am using the points at 0 and 1500 seconds because they are the easiest to identify the time for. Gradient = (change in mass of cathode) / time = 0.190 - 0 / 1500 - 0 = 0.190 / 1500 = 1.27 x 10-4 Faraday's Constant: I am using, again, the results obtained for 1500 seconds. Faraday's constant = (I . t . M) / (n . w) = (0.35 . 1500 . 63.55) / (2 . 0.190) = 87,799.34 C mol-1 � 4.58% Conclusion: From my data and calculations, I determined Faraday's Constant to be 87,799.34 C mol-1 � 4.58%. ...read more.


* Clean the electrodes with ethanol and tissue paper to get rid of grease prints. Inaccuracy when measuring the mass of the cathode after electrolysis The process of washing the cathode with distilled water to dispose of the copper sulphate solution that remained may also have involved the disposal of copper that was not fully attached to the cathode (caused by impurities). This would decrease the value for the increase in mass of the cathode greatly. * More care should be taken when handling the electrodes. * Tweezers could be used instead of fingers to minimise contact. * When washing the cathode, the distilled water could be squirted above the newly-formed layer of copper, and allowed to drip down into a beaker. This would be a gentler approach that would minimise loss of mass. When drying the cathode with tissue paper after washing, it was not fully dry, falsely increasing its mass when it was measured. * A hair-dryer could be used to dry the cathode. This would ensure that it is fully dry and it would also reduce the mass of copper lost due to rough handling. Problem/Error Source Prevention Method Impure CuSO4 used Filter solution before initiating investigation Irregular masses recorded Experiment should be repeated several times & an average taken 1 http://en.wikipedia.org/wiki/Faraday_constant - 9.24pm, 06/03/09 ?? ?? ?? ?? IB Chemistry Standard Brionna Wilson 12/11/2009 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Chemistry essays

  1. Electrochemical cells - investigate the effect of the temperature change of the anode electrolyte ...

    It may affect the averge voltage in both direction. - The immersion depth of electode: the immersion depth of electode will change a bit during experiment, especially in repeated experiment.

  2. How duration affects the rate of electrolysis in a Voltaic Cell

    and the copper electrode into the beaker with the copper sulphate solution and at the same time, start the stopwatch. Keep the stopwatch running until 200 seconds elapse. *Note- we will be recording the time every 5 minutes because 1 or 2 minutes simply isn't enough for the change to take place 7)

  1. IB chemistry revision notes

    electron from each atom of a mole of atoms in the gas state, to form one mole of cations in the gas phase, under s.t.p * * is positive. Across a Period * In every period the noble gas has the highest value.

  2. Atomic Structure Notes

    --> Na2+(g) + e- third ionisation energy Na2+(g) --> Na3+(g) + e- fourth ionisation energy Na3+(g) --> Na4+(g) + e- Factors influencing ionisation energy a. Distance of electron from nucleus The closer an electron is to the nucleus, the greater the force of attraction to the nucleus, and the more difficult it is to remove.

  1. Investigating a factor which may (or may not) affect the value of an equilibrium ...

    the substance added and if a substance is removed then it will move in the direction that can replace the removed substance 2. Change in pressure By changing the volume of a system of gases in equilibrium the pressure is affected.

  2. Electrolysis of copper sulphate

    Assign half of the electrodes to be the anodes and mark them with A1 to A5 using a permanent marker, then the other half will be the cathodes, mark these with C1 to C5(there should be 5 C?s and 5 A?s).

  1. Plan for an electrolysis experiment to determine the relationship between the current and the ...

    sulphate M, (mol/d) The 1.0M of copper (ii) sulphate solution is used for every trials. Time taken for electrolysis process to occur min (minute) For every experiment, the electrolytic cell is left for 20 minutes to allow electrolysis occur. Table 2 : the method of how to control the constant

  2. The chemistry of atmospheric and water pollution.

    Also the effect of acid rain has significant impacts on the ions found in water as sulfur and nitrogen oxides dissolve in the rain to form weak acids which when entering water increases the concentrations of sulfate, nitrate and hydrogen ions (decreasing pH).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work