An electrolytic cell can be used to plate gold onto other metal surfaces. The plating reaction is: Au (aq) e - - -> Au (s) Notice from the reaction that 1 mol e - plates out 1 mol Au (s). Use this stoichiometric relationship to determine how much time is required with an electrical current of 0.200 amp to plate out 0.400 g Au. The amp is a unit of electrical current equivalent to 1 C / s. (Hint: Recall that the charge of an electron is 1.60 x 10-19 C.)

Question

Marlon Mullins

Physics

3 September, 23:28

An electrolytic cell can be used to plate gold onto other metal surfaces. The plating reaction is: Au (aq) e - - -> Au (s) Notice from the reaction that 1 mol e - plates out 1 mol Au (s). Use this stoichiometric relationship to determine how much time is required with an electrical current of 0.200 amp to plate out 0.400 g Au. The amp is a unit of electrical current equivalent to 1 C / s. (Hint: Recall that the charge of an electron is 1.60 x 10-19 C.)

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Wilson Bright · Answer 1

Faraday's constant can be used to convert the charge (Q) into moles of electrons (n). The charge is the current (I) multiplied by the time

Q = I * t = n * F

Where

Q is charge

I is current = 0.2A

t is time = ?

n is number of mole

F is Faraday constant = 96500C/s

Mass of Au = 0.4 g = 0.0004kg

Molar mass of Au = 197 g/mol

Malar mass = mass / mole

n = 0.4 / 197

n = 2.03 * 10^-3 mol

n = 0.00203 mol

t = n * F / I

t = 0.00203 * 96500 / 0.2

t = 979.7 seconds

t = 16.32 minutes.