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  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 5 : Relationships among thermodynamic properties - Graphical representation of properties and processes"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 5.5 page : 208"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from scipy.optimize import fsolve\n",
      "\t\t\t\n",
      "# Variables\n",
      "R = 8314.3\n",
      "b = 0.0306 \t\t\t#m**3/kmol\n",
      "a = 0.548*10**6 \t\t\t#pa m**6/kmol**6\n",
      "T = 973.1\n",
      "P = 25*10**6 \t\t\t#Pa\n",
      "\t\t\t\n",
      "# Calculations\n",
      "Vi =  R*T/P\n",
      "#x = poly(0,'x')\n",
      "def f(x):\n",
      "    return P*x**2 *(x-b) +a*(x-b) - R*T*(x**2)\n",
      "#vec = roots(P*x**2 *(x-b) +a*(x-b) - R*T*(x**2))\n",
      "#vec = roots([P,(P*b+R*T),a,-a*b])\n",
      "vec = fsolve(f,0,full_output=1)\n",
      "volume =  vec[0]\n",
      "dH = 8.0906*10**6 -P*volume +0.548*10**6 /volume\n",
      "\t\t\t\n",
      "# Results\n",
      "print \"Change in enthalpy   =  %.2e J/kmol\"%(dH)\n",
      "\n",
      "\n",
      "# Note : Answer is different because fsolve function calculates differently. Please check manually.\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Change in enthalpy   =  2.21e+07 J/kmol\n"
       ]
      }
     ],
     "prompt_number": 1
    }
   ],
   "metadata": {}
  }
 ]
}