Faraday’s Law Essay

The Faraday is the electrical charge contained in a mole of electrons. In this experimented 2 values are determined. One by measuring the amount of charge needed to reduce H+ ions to h2 gas, and the other is as Cu atoms are oxidized to Cu2+ ions. The chemical formula applied during this lab was Cu + 2H+-> Cu+2 + H2. Procedure Cleaned a copper plate in 2M HNO3, weighed it and recorded data. Mixed 100ml distilled water with 50ml of 3M sulfuric acid in a 200ml beaker. Put buret upside down into beaker and placed cathode up inside buret. Connected side aspirator to water aspirator. Set voltage regulator to zero turned power on; voltage was put to 190 amps and started recording the time. Regulated dial to keep current constant until 25ml of hydrogen had filled the buret. Data Calculations 1. Average current during electrolysis = 190 amps 2. Elapsed time in electrolysis (seconds) = 1080 seconds 3. Coulombs transferred in electrolysis = . 1900 x 1080 = 205. 2 coulombs 4. Mass loss of copper anode = 6. 6061g – 6. 5427g = . 0634g 5. Moles of Cu lost = . 0634/63. 54= 9. 98 x 10^-4 moles 6. Moles of e- released by Cu oxidation = 2 x 9. 98 x 10^-4 = . 00200 moles 7. Value of faraday for Cu oxidation = 205. 2/. 00200 = 1. 03 x 10^ -5 coulombs/moles 8. Mercury equivalent of water column = (1. 00g/mol)(337mm)=(H hg) = 24. 8 mm hg 9. Partial pressure of water vapor = 21. 068 (mm Hg) 10. partial pressure of hydrogen gas produced = 762. 5 = 24. 8 + 21. 068 + P h2 P h2 = 716. 6(mm Hg) 11. Moles of H2 formed = (. 943)(25. 3) = N(82. 05)(296) N=9. 8 x 10^-4 moles 12. Moles of e- use top reduce H+ = 2 x 9. 8 x 10^ – 4 = . 00196 moles 13. Value of Faraday of H+ reduction =205. 2/. 00196 = 1. 04 x 10 ^5 (coulombs/moles) Discussion 1. 04 x 10^5 coulombs was the calculated value for electrical charge contained in a mole of electrons. The equation applied for this experiment was Cu + 2H+ -> Cu+2 + H2. The experimental value calculated was 104,000, compared to the accepted value which is 96,500 coulombs/moles; the values are close in range. The percent error was 7. 77%, some possible reasons for error could producing too much or too little h2 in the buret. Another possible error could be not enough Cu+.