Question

How many minutes will it take to electroplate 41.1 g of gold by running 5.00 A of current through a solution of Au+(aq)? Express your answer to three significant figures and include the appropriate units.

Answer 1

molar mass of gold = 197 g/mol

Electrolysis equation is:

Au+ + 1e- ------> Au

1 mol of Au requires 1 mol of electron

1 mol of electron = 96485 C

So,1 mol of Au requires 96485 C

let us calculate mol of element deposited:

use

number of mol, n = mass/molar mass

= 41.1 g /197 g/mol

= 0.20863 mol

total charge = mol of element deposited * charge required for 1 mol

= 0.20863*96485

= 20129.6117 C

use

time = Q/i

= 20129.6117/5

= 4026 seconds

= 4026/60 minutes

= 67.1 minutes

Answer: 67.1 minutes

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