A current of 4.60 A is passed through a Cr(NO3)2 solution for 1.10 hours. How much chromium is plated out of the solution?
see other post
To find out how much chromium is plated out of the solution, you need to calculate the amount of charge that passed through the solution during the given time.
The amount of charge (Q) is calculated using the formula: Q = I * t, where I is the current in amperes, and t is the time in seconds.
Given:
Current (I) = 4.60 A
Time (t) = 1.10 hours
First, we need to convert the time from hours to seconds, as the standard unit for time in the formula is seconds.
1.10 hours * 60 minutes per hour * 60 seconds per minute = 3960 seconds (rounded to the nearest whole number)
Now we can calculate the charge:
Q = 4.60 A * 3960 seconds = 18,216 Coulombs (rounded to the nearest whole number)
The next step is to determine the amount of chromium plated out of the solution using Faraday's Law of Electrolysis. The equation is:
m = (Q * M) / (n * F)
Where:
m is the mass of the substance plated out (in grams),
Q is the charge passed through the solution (in Coulombs),
M is the molar mass of the substance (in grams/mole),
n is the number of electrons transferred in the balanced chemical equation,
F is Faraday's constant (approximately 96,485 Coulombs/mole)
For Cr(NO3)2, the balanced chemical equation is:
Cr(NO3)2 + 2e- → Cr(s) + 2NO3-
The number of electrons transferred (n) is 2.
The molar mass of Cr(NO3)2 can be found in the periodic table:
Cr = 52 g/mole
N = 14 g/mole
O = 16 g/mole (x 3)
Molar mass of Cr(NO3)2 = 52 g/mole + 14 g/mole + (16 g/mole * 3) = 160 g/mole
Now we can calculate the mass of chromium plated out:
m = (18216 C * 160 g/mole) / (2 * 96485 C/mole) ≈ 14.91 g
Therefore, approximately 14.91 grams of chromium is plated out of the solution.