# Chemistry help??? Calculate the mass of magnesium formed upon passage of a current

a) The half-reac2on for formation on of Mg upon electrolysis of molten MgCl2 is

Mg2+ +2e→Mg.

Calculate the mass of magnesium formed upon passage of a current of 60.0 A for a period of 4.00 × 103 s.

(b) How many seconds would be required to produce 50.0 g of Mg from MgCl2 if the current is 100.0 A?

edited Apr 23, 2015

Step 1:

(a)

The current in the electrolysis of magnesium chloride is 60.0 A.

The time taken for the electrolysis of magnesium chloride is  Sec.

Half-reaction for formation of magnesium chloride : .

Charge of the magnesium ion is

Convert charge into Moles per electron :

Step 2:

Now convert amount of substance in moles.

Find out the Molecular weight.

Amount of magnesium is 302.23 g.

Solution:

Amount of magnesium is 302.23 g.

Step 1:

(b)

The current in the electrolysis of magnesium chloride is 100.0 A.

The amount of the magnesium chloride is 50.0 g

Half-reaction for formation of magnesium chloride : .

Find out the amount of the magnesium chloride in moles.

Molecular weight of the magnesium chloride is 95.211 g/mol.

Step 2:

Total amount of magnesium chloride for 2 electrons.

Charge of the substance :

The current in the electrolysis of magnesium chloride:

The time taken for the electrolysis of magnesium chloride is  Sec.

Solution:

The time taken for the electrolysis of magnesium chloride is Sec.