How many hours to two significant figures would it take to p

How many hours (to two significant figures) would it take to plate out 1.000 kilograms of aluminum (26.98 g/mol) from a solution of Al(NO₃)₃ with a current of 125.0 A?

Convert the mass of Al to moles of Al then to moles of electrons needed. 96500 Coulombs of charge are needed for each mole of electrons.

Coulombs = (Amperes) x (seconds) and there are 3600 seconds in one hour.

Please show answer, and explain thanks.

Solution

Al3+ + 3 e- => Al

Moles of Al = mass/molar mass of Al

= 1000/26.98 = 37.064 mol


Moles of electrons = 3 x moles of Al

= 3 x 37.064 = 111.19 mol


Charge = moles of electrons x Faraday constant

= 111.19 x 96500 = 1.073 x 10^7 C


Time = charge/current

= 1.073 x 10^7/125.0

= 85840 s = 24 hours