Final answer:
To electroplate 60 g of calcium from molten calcium chloride (CaCl2), a current of 5.0 A must be maintained for 8.0 hours.
Step-by-step explanation:
To determine the time required to electroplate 60 g of calcium from molten calcium chloride (CaCl2), we need to convert the mass of calcium to moles, and then calculate the amount of charge (in coulombs) required to deposit that many moles of calcium.
Finally, we can calculate the time using the current.
Step 1: Convert mass of calcium to moles:
Number of moles = mass / molar mass
= 60 g / 40.08 g/mol
= 1.497 mol
Step 2: Calculate the amount of charge:
Charge = number of moles x Avogadro's number x charge of an electron
Charge = 1.497 mol x (6.022 x 10^23 mol^-1) x (1.602 x 10^-19 C)
Charge = 1.497 x 6.022 x 1.602 x 10^4 C
= 144.1 x 10^4 C
Step 3: Calculate the time using the current:
Current = 5.0 A
Charge = Current x Time
Time = Charge / Current
= 144.1 x 10^4 C / 5.0 A
= 28.8 x 10^4 s
Converting seconds to hours:
Time = 28.8 x 10^4 s x (1 h / 3600 s)
= 8.0 hours