for how long must a current of 1.5 amperes be passed through an aqueous solution of a copper salt during electrolysis in order to deposit 2.50g of copper (cu=63.5)
It will require 95,485 coulombs to deposit 63.5/2 = 31.8 g Cu. You want 2.5 g Cu so it will require 96,485 C x (2.5/31.8 = 0.787 Coulombs.
C = amperes x seconds. You know C and amperes, calculate seconds.
To determine the time required for the current to deposit 2.50g of copper during electrolysis, we need to utilize Faraday's laws of electrolysis.
Faraday's laws state that the amount of substance (in moles) deposited or liberated during electrolysis is directly proportional to the quantity of electric charge passed through the electrolyte. The relationship can be expressed as:
m = (Q * M) / (n * F)
Where:
m = mass of the substance deposited (in grams)
Q = electric charge passed (in Coulombs)
M = molar mass of the substance (in grams per mole)
n = number of electrons involved in the electrochemical reaction
F = Faraday's constant (approximately 96,500 Coulombs per mole of electrons)
In this case, we want to calculate the time required to deposit 2.50g of copper by passing a current of 1.5 amperes. Here's how we can find the answer:
1. Determine the molar mass of copper (Cu):
Molar mass of Cu = 63.5g/mol
2. Calculate the number of moles of Cu deposited:
moles of Cu = mass of Cu / molar mass of Cu
= 2.50g / 63.5g/mol
3. Determine the number of electrons involved in the electrochemical reaction:
In this case, each Cu2+ ion gains two electrons to form Cu, so n = 2.
4. Calculate the electric charge passed (Q):
Q = I * t
We are given that I (current) = 1.5 amperes. We need to solve for time (t).
5. Rearrange the equation to solve for time:
t = Q / I
6. Substitute the values into the equation to calculate time:
t = (moles of Cu * F) / I
Substitute the values found in steps 2 and 3, and the value for Faraday's constant (approximately 96,500 C/mol):
t = (moles of Cu * 96,500 C/mol) / 1.5 A
Plug in the values and calculate the time required.