Electro Chemistry

Question

Calculate the grams of Sr(s) produced when 1.93 Amperes are passed through the cell shown below for 6.58 hours.

Sr^+2(aq) + 2Cl^-1(aq) ---> Sr(s) + Cl_2(g)

Answer 1

Find coulombs:

1.93 amps = 1.93 Coulombs / sec

6.58 hr x 60 min/hr x 60 sec/min = 23,688 sec

1.93 C/sec x 23,688 sec = 45,718 Coulombs

Find moles of electrons transferred per mol Sr(s) formed:

Sr2+ + 2e- = Sr(s)

2 mols electrons are transferred per mol Sr(s) formed

Using the Faraday constant (96.485 C/mol e-), find mols Sr(s) formed:

45,718 C x 1 mol e- / 96,485 C x 1 mol Sr / 2 mols e- = 0.237 mols Sr(s) formed

Convert mols Sr to grams Sr:

0.237 mols Sr x 87.6 g Sr / mol Sr = 20.8 g Sr