(a) Calculate the mass of Li formed by electrolysis of molten LiCl by a current of 8.2 104 A flowing for a period of 14 hr. Assume the electrolytic cell is 70. percent efficient.
answer = 210000
(b) What is the energy requirement for this electrolysis per mole of Li formed if the applied emf is +8.4 V?
answer in kWh/mol
2007-11-18 14:04:02 · 1 answers · asked by softshimmer 2 in Science & Mathematics ➔ Chemistry
please help!..im clueless
2007-11-18 14:04:34 · update #1
14 hr = 14*3600s
8.2x10^4 A = 8.2x10^4 Coulomb /second = 8.2x10^4 C/s
1 Faraday = 96485C
Molar mass of Li: 6.941 g/mol
{(8.2x10^4 C/s)*(14*3600s)*(6.941 g/mol)/(96485C/mol)}*70%
= 2.1x10^5 gram
(96485C/mol)*(8.4V) = 8.10x10^5 (J/mol)
= 8.10x10^5 (Ws/mol)
Devide by 3600s/h to get:
8.10x10^5 (Ws/mol) = 225 Wh/mol = 0.23 kWh/mol
2007-11-20 18:08:20 · answer #1 · answered by Hahaha 7 · 1⤊ 3⤋