1. The problem statement, all variables and given/known data A sphere 100 mm diameter is to be coated with chromium from a solution containing chromium in the six valent (hexavalent) state. How much time would be needed to produce a coating 20 μm thick if: • the current is 20 A • the cathodic efficiency is 15% • the atomic weight and density of chromium are 52 and 7.2 gcm–3 respectively 2. Relevant equations (w=ItA/6F) x (efficiency (%) / 100) 3. The attempt at a solution Weight deposited, W = Current, I = 20 amps Atomic Weight, A = 52 gcm-3 Faraday's constant, F = 96500 Efficiency = 15% sphere surface area = 4*π*502 = 31415.92mm2 im not sure where to start here. can anyone advise?