Question

Two cells, one containing AgNO3 and the other SnCl2, are connected in series and a given quantity of electricity passes through both. If 2.00 g of silver is deposited in one cell, how many grams of tin are deposited in the other?

Answer 1

The mass of tin deposited is 1.1 g.

The steps involved are:

1. Write the balanced equation.

2. Use conversion factors to convert mass of Ag → moles of Ag → moles of Sn → mass of Sn

Step 1

The balanced equation for a galvanic cell is

2 × [Ag⁺ + e⁻ → Ag];

E

°

= +0.80 V

1 ×[Sn →Sn²⁺ + 2e⁻];

E

°

= +0.14 V

2Ag⁺ + Sn → 2Ag + Sn²⁺;

E

°

= +0.94 V

This equation tells you that, when you force electricity between two cells in series, the moles of tin deposited are twice the moles of silver.

Step 2

Mass of Sn = 2.0 g g Ag ×

1

mol Ag

107.9

g Ag

×

1

mol Sn

2

mol Ag

×

118.7

g Sn

1

mol Sn

= 1.1 g Sn (2 significant figures)

is it true