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   "source": [
    "# Appendix D"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Change in gibbs free energy at 298K : 457.179 KJ\n",
      "Change in gibbs free energy at 298K : 271.04 KJ\n"
     ]
    }
   ],
   "source": [
    "# -*- coding: utf8 -*-\n",
    "from __future__ import division\n",
    "#Example: 16.2\n",
    "'''Determine the value of \u0002G0 for the reaction 2H2O \u0003\u0004 2H2 + O2 at 25◦C and at 2000 K,\n",
    "with the water in the gaseous phase.'''\n",
    "\n",
    "#Keys:\n",
    "#1-H2\n",
    "#2-O2\n",
    "#3-H2O\n",
    "\n",
    "#Variable Declaration: \n",
    "def dG(T1,Hf1,Hf2,Hf3,Sf1,Sf2,sf3):\n",
    "\tdH = 2*Hf1+Hf2-2*Hf3\t#Change in enthalpy in kJ\n",
    "\tdS = 2*Sf1+Sf2-2*sf3 \t#Change in entropy in J/K\n",
    "\tdG = dH-T1*dS/1000\t#change n gibbs free energy in kJ\n",
    "\treturn dG\n",
    "\n",
    "#Results:\n",
    "print 'Change in gibbs free energy at 298K :',round(dG(298,0, 0, -241.826, 130.678,205.148,188.834),3),\"KJ\"\n",
    "print 'Change in gibbs free energy at 298K :',round(dG(2000,52.942, 59.176, -241.826+72.788,188.419,268.748,264.769),3),\"KJ\"\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Equilibrium constant at 298K:  -184.51\n",
      "Equilibrium constant at 2000K:  -16.299\n"
     ]
    }
   ],
   "source": [
    "# -*- coding: utf8 -*-\n",
    "from __future__ import division\n",
    "#Example: 16.3\n",
    "'''Determine the equilibrium constant K, expressed as ln K, for the reaction 2H2O <--->\n",
    "2H2 + O2 at 25◦C and at 2000 K.'''\n",
    "\n",
    "#Variable Declaration: \n",
    "dG1 = -457.166\t\t\t#change in gibbs free energy at temp 298 K from example2 in kJ\n",
    "dG2 = -271.040\t\t\t#change in gibbs free energy at temp 2000 K from example2 n kJ\n",
    "T1 = 298\t\t\t\t#K\n",
    "T2 = 2000\t\t\t\t#K\n",
    "R = 8.3145\t\t\t\t#gas constant\n",
    "\n",
    "#Calculations:\n",
    "K1 = dG1*1000/(R*T1)\n",
    "K2 = dG2*1000/(R*T2)\n",
    "\n",
    "#Results:\n",
    "print 'Equilibrium constant at 298K: ',round(K1,2)\n",
    "print 'Equilibrium constant at 2000K: ',round(K2,3)"
   ]
  }
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