Calculate the mass of Li formed by electrolysis of molten LiCl by a current of 6.7×104 A flowing for a period of 23 h . Assume the electrolytic cell is 86 % efficient.
What is the energy requirement for this electrolysis per mole of Li formed if the applied emf is + 7.3 V ?
each atom requires one electron
each electron has a charge of XXXXX columb
each ampere is a flow of one coulomb/sec
in 23 hours, yyyyy seconds have passed.
so number atoms in 23 hours must be..
Number=yyyy*current/xxxx
moles=number/avag number
energy= voltage*current/moles
To calculate the mass of Li formed by electrolysis, we need to use Faraday's laws of electrolysis and the molar mass of Li.
1. First, calculate the charge passing through the cell using Faraday's laws of electrolysis:
- Faraday's constant (F) = 96,485 C/mol
- The time in seconds = 23 hours * 3600 seconds/hour = 82,800 seconds
- The charge (Q) passing through the cell = current (I) * time (t)
- Q = 6.7×10^4 A * 82,800 s
2. Next, calculate the number of moles of electrons transferred using Faraday's laws of electrolysis:
- One mole of electrons corresponds to 1 Faraday of charge:
- Moles of electrons (n) = Q / F
3. Since the electrolytic cell is 86% efficient, the moles of electrons transferred will be:
- Actual moles of electrons transferred = n * efficiency
- Moles of electrons transferred = n * 0.86
4. Calculate the number of moles of Li formed by assuming that each mole of Li requires one mole of electrons:
- Moles of Li formed = Moles of electrons transferred
5. Finally, calculate the mass of Li formed by multiplying the moles of Li formed by its molar mass:
- Molar mass of Li = 6.941 g/mol
- Mass of Li formed = Moles of Li formed * Molar mass of Li
To calculate the energy requirement per mole of Li formed, we can use the formula:
Energy requirement = (V * Q) / (n * F)
where V is the applied voltage, Q is the charge passed (in coulombs), n is the moles of electrons transferred, and F is Faraday's constant.
6. Calculate the energy requirement per mole of Li formed:
- Energy requirement = (7.3 V * Q) / (n * F)
Now, let's plug in the values and calculate:
Step 1:
Q = 6.7×10^4 A * 82,800 s
Step 2:
n = Q / F
Step 3 (efficiency = 0.86):
Actual moles of electrons transferred = n * 0.86
Step 4:
Moles of Li formed = Actual moles of electrons transferred
Step 5 (Molar mass of Li = 6.941 g/mol):
Mass of Li formed = Moles of Li formed * Molar mass of Li
Step 6:
Energy requirement = (7.3 V * Q) / (n * F)
By following these steps and plugging in the given values, you can find the mass of Li formed and the energy requirement per mole of Li formed in the electrolysis process.