A rectangular steel bumper (surface area to be plated = 0.250 m ) is electroplated…
CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry
Problem
A rectangular steel bumper (surface area to be plated = 0.250 m2) is electroplated with chromium metal in an electrolytic bath containing Cr3+(aq). A constant current of 2.00 A is passed through the cell for 3.00 h. The plating process is 82.0 % efficient, meaning that only that fraction of the total current reduces Cr3+ to Cr(s); the remainder drives side reactions. The density of chromium metal is 7.19 g cm−3. Atomic mass of Cr = 52.00 g mol−1.
(a) Determine the total electric charge, in coulombs, that actually produces chromium metal during the 3.00 h plating process.
(b) Calculate the mass of chromium deposited on the bumper.
(c) Assuming the chromium coats the bumper uniformly, calculate the average thickness of the chromium layer in micrometres (µm).