Metallic Magnesium can be made from electrolysis of molten MgCl2. What mass of Mg is formed by passing a current of 4.55A through a molten MgCl2 for 3.50 days?
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To calculate the mass of magnesium formed by passing a current through molten MgCl2, we need to use Faraday's laws of electrolysis and the molar mass of magnesium.
First, let's find the total charge passed through the electrolyte using Faraday's second law, which states that the amount of substance produced by an electric current is directly proportional to the quantity of electricity passed through it.
The formula for calculating the quantity of electricity (Q) is:
Q = I * t
where I is the current in amperes (A) and t is the time in seconds (s).
However, in this problem, the time is given in days, so we need to convert it to seconds:
t = 3.50 days * 24 hours/day * 60 minutes/hour * 60 seconds/minute
Next, we need to use Faraday's constant, which is the charge per mole of electrons:
F = 96500 C/mol
To find the moles of electrons (n), we divide the total charge (Q) by Faraday's constant:
n = Q / F
Since the reaction for the electrolysis of MgCl2 involves the transfer of 2 moles of electrons per mole of magnesium produced, we divide the moles of electrons (n) by 2 to find the moles of Mg:
moles of Mg = n / 2
Finally, to calculate the mass of magnesium (m), we multiply the moles of Mg by the molar mass of magnesium (Mg):
m = moles of Mg * molar mass of Mg
The molar mass of magnesium is 24.31 g/mol.
Let's perform the calculations:
Step 1: Convert the time from days to seconds
t = 3.50 days * 24 hours/day * 60 minutes/hour * 60 seconds/minute
Step 2: Calculate the total charge passed through the electrolyte
Q = I * t
Q = 4.55 A * t (now in seconds)
Step 3: Calculate the moles of electrons
n = Q / F
Step 4: Calculate the moles of magnesium
moles of Mg = n / 2
Step 5: Calculate the mass of magnesium
m = moles of Mg * molar mass of Mg
By following these steps and plugging in the given values, you can find the mass of magnesium formed by passing a current of 4.55 A through molten MgCl2 for 3.50 days.