Question

Chromium metal is plated onto a car bumper at a current of 10.0 amperes for 100 seconds. The plating bath contains chromium in the form of CrO42− ions. How many grams of Cr are deposited in this process? (The atomic weight of Cr is 51.996 amu.)

Answer 1

0.54g of Cr

Step-by-step explanation:

Current (I) = 10A

Time (t) = 100s

Molecular mass of Cr = 51.996 amu

Faraday's first law of electrolysis states that

The mass of the substance (m) of a given substance deposited at an electrode is directly proportional to the quantity of electricity or charge (Q) passed

m = nQ

M = mass of the substance

n = electrochemical constant

Q = charge passed through it

Q = IT

Q = (10 * 100) = 1000C

1 moles = molarmass = Faraday's constant (96500C)

Molar mass = Faraday's constant (96500C)

51.996 g = 96500C

How many grams will be liberated with 1000C

51.996g = 96500C

Xg = 1000C

X = (1000 * 51.996) / 96500

X = 51996 / 96500

X = 0.5388g = 0.54 g of Cr will be deposited