Assume that your electrolysis passes a current of 2.50 amps (= Coulombs/sec) for
ID: 962227 • Letter: A
Question
Assume that your electrolysis passes a current of 2.50 amps (= Coulombs/sec) for 12 minutes. a. How much charge (in Coulombs) is passed through the cell during this time [2]? b. How many moles of electrons are passed through the cell during this time? 1 mole of electrons has a charge of 96, 500 C. (This value, 96, 500 c/mol is callcd Faraday's Constant) [2]. c. How many moles of hydrogen gas are produced? What is the mass of the hydrogen produced during this time. (The molecular mass of hydrogen, H_2 is 2.0 g/mol) [2]. c. How many moles of chlorine gas are produced? What is the mass of the chlorine produced during this time. (The molecular mass of chlorine. Cl_2, is 71.0 g/mol [2].Explanation / Answer
1
1 amp of current is equal to 1 coulomb of charge passing a point in one second.
12 min = 60 sec/ 1.0 min* 12 min=720 s
2.50 amps or C/ s x 720 s
= 1800 coulombs
2
Given that
1amp = 1coulomb/s
1F = 96500 C / mol e-
[2.50 moles e-/720s] x [96,500coulombs/1mole e-]
= 335.07 coulombs/s (or amps.)
3
I = 2.5 A
t = 12 min = 15 x 60 s = 720s
Q = I t = 2.5 x 720 = 1800 C
For hydrogen,
2H^ + + 2 e = H2
Therefore, 2 mole of electron produces 1 mole of H2(g)
2 F of electricity produces 1 mol of Hydrogen
2x 96500 C of electricity produces 1 mol of Hydrogen
1800 C will produce mol of Hydrogen
= 1 mol x 1800 /2 x 96500
=9.33*10^-3 mol
Molar mass of H2 gas = 2.0 g/ mol
Amount of H2 gas = 2.0g/ mol * 9.33*10^-3 mol
= 0.001866 g H2
4
I = 2.5 A
t = 12 min = 15 x 60 s = 720s
Q = I t = 2.5 x 720 = 1800 C
For Chlorine
2Cl^ + + 2 e = Cl22
Therefore, 2 mole of electron produces 1 mole of Cl2(g)
2 F of electricity produces 1 mol of Cl
2x 96500 C of electricity produces 1 mol of Cl
1800 C will produce mol of Cl
= 1 mol x 1800 /2 x 96500
=9.33*10^-3 mol
Molar mass of Cl2 gas = 71.0 g/ mol
Amount of Cl2 gas = 71.0g/ mol * 9.33*10^-3 mol
= 0.66243 g Cl2