{
"metadata": {
"name": "",
"signature": "sha256:d710461b968e986411ee49bb4f3e24c283e59536cefcb736abd7424eef7f3627"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 11: Electrochemical Cells, Batteries, and Fuel Cells"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.1, Page Number 256"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import log, sqrt\n",
"\n",
"#Variable Declaration\n",
"aH = 0.770 #Activity of \n",
"fH2 = 1.13 #Fugacity of Hydrogen gas\n",
"E0 = 0.0 #Std. electrode potential, V\n",
"n = 1.0 #Number of electrons transfered\n",
"\n",
"#Calculations\n",
"E = E0 - (0.05916/n)*log(aH/sqrt(fH2),10)\n",
"\n",
"#Results\n",
"print 'The potential of H+/H2 half cell %5.4f V'%E"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"THe potential of H+/H2 half cell 0.00829 V\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.2, Page Number 256"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import log, sqrt\n",
"\n",
"#Variable Declaration\n",
"E0r1 = -0.877 #Std Electrod potential for Rx2 : Al3+ + 3e- ------> Al (s) \n",
"E0r2 = -1.660 #Std Electrod potential for Rx2 : Al3+ + 3e- ------> Al (s)\n",
"E0r3 = +0.071 #Std Electrod potential for Rx3 : AgBr (s) + e- ------> Ag(s) +Br- (aq.)\n",
"\n",
"#Calculations\n",
"#3Fe(OH)2 (s)+ 2Al (s) <---------> 3Fe (s) + 6(OH-) + 2Al3+\n",
"E0a = 3*E0r1 + (-2)*E0r2\n",
"#Fe (s) + 2OH- + 2AgBr (s) -------> Fe(OH)2 (s) + 2Ag(s) + 2Br- (aq.)\n",
"E0b = -E0r1 + (2)*E0r3\n",
"\n",
"#Results\n",
"print '%5.3f %5.3f'%(E0a,E0b)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0.689 1.019\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.3, Page Number 257"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Variable Declaration\n",
"E01 = 0.771 #Rx1 : Fe3+ + e- -----> Fe2+\n",
"E02 = -0.447 #Rx2 : Fe2+ + 2e- -----> Fe\n",
"F = 96485 #Faraday constant, C/mol\n",
"n1,n2,n3 = 1.,2.,3.\n",
"\n",
"#Calculations\n",
"dG01 = -n1*F*E01\n",
"dG02 = -n2*F*E02\n",
" #For overall reaction\n",
"dG0 = dG01 + dG02\n",
"E0Fe3byFe = -dG0/(n3*F)\n",
"\n",
"#Results\n",
"print 'E0 for overall reaction is %5.3f V'%(E0Fe3byFe)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"E0 for overall reaction is -0.041 V\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.4, Page Number 258"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"E01 = +1.36 #Std. electrode potential for Cl2/Cl\n",
"dE0bydT = -1.20e-3 #V/K\n",
"F = 96485 #Faraday constant, C/mol\n",
"n = 2.\n",
"S0H = 0.0 #Std. entropy J/(K.mol) for H+ ,Cl-,H2, Cl2 \n",
"S0Cl = 56.5\n",
"S0H2 = 130.7\n",
"S0Cl2 = 223.1\n",
"nH, nCl, nH2, nCl2 = 2, 2, -1,-1\n",
"#Calculations\n",
"dS01 = n*F*dE0bydT\n",
"dS02 =nH*S0H + nCl*S0Cl + nH2*S0H2 + nCl2*S0Cl2\n",
"\n",
"#Results\n",
"print 'Std. entropy change of reaction from dE0bydT is %4.2e and\\nStd entropy values is %4.2e V'%(dS01,dS02)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Std. entropy change of reaction from dE0bydT is -2.32e+02 and\n",
"Std entropy values is -2.41e+02 V\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.5, Page Number 259"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import exp\n",
"#Variable Declaration\n",
"E0 = +1.10 #Std. electrode potential for Danniel cell, V\n",
" #Zn(s) + Cu++ -----> Zn2+ + Cu\n",
"T = 298.15 #V/K\n",
"F = 96485 #Faraday constant, C/mol\n",
"n = 2.\n",
"R = 8.314 #Gas constant, J/(mol.K)\n",
"\n",
"#Calculations\n",
"K = exp(n*F*E0/(R*T))\n",
"\n",
"#Results\n",
"print 'Equilibrium constant for reaction is %4.2e'%(K)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Equilibrium constant for reaction is 1.55e+37\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.6, Page Number 259"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"E = +0.29 #Cell emf, V\n",
"\n",
"#Calculations\n",
"Ksp = 10**(-n*E/0.05916)\n",
"\n",
"#Results\n",
"print 'Equilibrium constant for reaction is %4.2e'%(Ksp)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Equilibrium constant for reaction is 1.57e-10\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 11.8, Page Number 262"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"E = +1.51 #EMF for reduction of permangnet, V\n",
"E01 = -0.7618 #Zn2+ + 2e- --------> Zn (s)\n",
"E02 = +0.7996 #Ag+ + e- --------> Ag (s)\n",
"E03 = +1.6920 #Au+ + e- --------> Au (s) \n",
"\n",
"#Calculations\n",
"EZn = E - E01\n",
"EAg = E - E02\n",
"EAu = E - E03\n",
"animals = {\"parrot\": 2, \"fish\": 6}\n",
"Er = {\"Zn\":EZn,\"Ag\":EAg,\"Au\":EAu}\n",
"#Results\n",
"print 'Cell potentials for Zn, Ag, Au are %4.2f V, %4.2f V, and %4.2f V'%(EZn, EAg,EAu)\n",
"for i in Er:\n",
" if Er[i] >0.0:\n",
" print '%s has positive cell potential of %4.3f V and Can be oxidized bypermangnate ion' %(i,Er[i])\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Cell potentials for Zn, Ag, Au are 2.27 V, 0.71 V, and -0.18 V\n",
"Zn has positive cell potential of 2.272 V and Can be oxidized bypermangnate ion\n",
"Ag has positive cell potential of 0.710 V and Can be oxidized bypermangnate ion\n"
]
}
],
"prompt_number": 25
}
],
"metadata": {}
}
]
}