Commercial electrolytic cells for producing aluminum

operate at 5.0 V and 100,000 A.

(a) How long does it take to produce exactly 1 metric ton (1000 kg)

of aluminum?

(b) How much electrical power (in kilowatt-hours, kW·h) is used

(1 W = 1 J/s; 1 kW·h = 3.6×103

kJ)?

(c) If electricity costs $0.123 per kW·h and cell efficiency is 90.%,

what is the cost of electricity to produce exactly 1 lb of aluminum?