# Electrochem

posted by
**Keith**
.

A baby's spoon with an area of 6.25 cm^2 is plated with silver from AgNO3 using a current of 2.00 A for two hours and 25 minutes.

a) If the current efficiency is 82.0%, how many grams of silver are plated?

b) What is the thickness of the silver plate formed (d= 10.5 g/cm^3)?

I think the efficiency part is tripping me up; I can't even think of how to start the problem. I'm guessing the efficiency has something to do with the amount done over the amount of time taken? But still; I don't know how I can relate the area of the spoon to grams of silver. Any help is appreciated.

Just calculate the current OR coulombs and multiply by 0.82 and proceed. That 82% simply means that 100 A appears to be only 82 A or 500 coulombs (just a made up number) appears to be only 0.82*500).