A current of 5.61 A is pass through a Ni(NO3)2 solution. How long (in hours) would this current have to be applied to plate out 9.00 g of nickel?
To determine the time required, we need to use Faraday's law of electrolysis, which relates the mass of a substance produced or consumed in an electrolytic cell to the amount of charge passed through it.
The equation for Faraday's law is:
m = (Q * M) / (n * F)
Where:
m is the mass of the substance (in grams)
Q is the charge passed through the cell (in coulombs)
M is the molar mass of the substance (in grams/mol)
n is the number of moles of electrons involved in the reaction
F is Faraday's constant (approximately 96485 C/mol)
In this case, we want to find the time required (t) to plate out 9.00 g of nickel, so let's rearrange the equation:
t = (m * n * F) / (Q * M)
First, we need to find the number of moles of electrons involved in the reaction. For nickel, the oxidation state is 2+, so the reaction involves the reduction of Ni2+ ions:
Ni2+ + 2e- -> Ni
In this reaction, 2 moles of electrons are required to plate out 1 mole of Ni. Therefore, n = 2.
Next, we need to find the molar mass of nickel (M). The molar mass of nickel is 58.69 g/mol.
Finally, we substitute the given values into the equation to find the time required (t):
t = (9.00 g * 2 * 96485 C/mol) / (5.61 A * 60 s/min * 60 min/h * 58.69 g/mol)
Calculating this expression will give us the time required in hours.
It takes 95,485 C to plate out 1 gram equivalent of Ni which is 58.7/2 grams or about 30 grams. We want 9.00 grams; therefore,
96,485 x (9.00/about 30) = Coulombs needed. = estimated 30,000 coulombs.
Then C = amps x seconds
You know C and amps, solve for seconds and convert to hours.