Question

Electrolysis of a solution of an unknown metal increased the cathode mass by 0.0434 grams when a current of 0.50 A passed through the cell for 5 minutes. Further research determined the charge on the metal to be + 2. What is the identity of the metal?

Answer 1

The metal is iron (Fe^2+)

Step-by-step explanation:

Step 1: Data given

Mass of the metal = 0.0434 grams

Current = 0.50 A

charge on the metal = + 2

Time = 5 minutes = 300 secons

Faraday constant = 96485 A*s

Step 2: The equation for a metal with charge +2

M^2+ + 2- → M

Step 3: Calculate number of moles of metal

Number of moles metal = seconds * current / (coulomb * #electrons)

Number of moles metal = 300 * 0.50 / (96485 * 2)

Number of moles metal = 7.77*10^-4 moles

Step 4: Calculate molar mass of metal

Molar mass = mass / moles

Molar mass = 0.0434 grams / 7.77 *10^-4 moles

Molar mass = 55.86 g/mol

The metal is iron (Fe^2+)