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diff --git a/Physical_Chemistry_by_G_H_Duffey/1-Matter_and_its_atomic_nature.ipynb b/Physical_Chemistry_by_G_H_Duffey/1-Matter_and_its_atomic_nature.ipynb
new file mode 100644
index 0000000..1914ab2
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/1-Matter_and_its_atomic_nature.ipynb
@@ -0,0 +1,171 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 1: Matter and its atomic nature"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.10: Example_10.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"A=[-1 -1 -1 ]\n",
+"B=[1 1 -1]\n",
+"//calculations\n",
+"Ad=sqrt(1+1+1)\n",
+"Bd=sqrt(1+1+1)\n",
+"dot=A.*B /(Ad*Bd) \n",
+"theta=acosd(dot)\n",
+"//results\n",
+"printf('Angle = %.2f degrees',theta(1,1))"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"l=0.71 *10^-8 //cm\n",
+"n=200 //lines/cm\n",
+"v=0.00145 //radian\n",
+"//calculations\n",
+"d=1/n\n",
+"phi2=2*l/d +v^2\n",
+"phi=sqrt(phi2)\n",
+"//results\n",
+"printf('Angle required = %.2e radian',phi)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"angle=37.25 //degrees\n",
+"l=1.539 //A\n",
+"n=1 //order\n",
+"//calculations\n",
+"d=n*l/(2*sind(angle))\n",
+"//results\n",
+"printf('Interplanar distance = %.3f A',d)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"r1=sqrt(3)\n",
+"r2=1\n",
+"//calculations\n",
+"ratio=r1-r2\n",
+"//results\n",
+"printf('Ratio of radii = %.3f',ratio)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"d=2.64 //g/cc\n",
+"l=4.016*10^-8 //cm\n",
+"n=4\n",
+"M=25.94 //g/mol\n",
+"//calculations\n",
+"m=d*l^3 /n\n",
+"N0=M/m\n",
+"//results\n",
+"printf('Avagadro number = %.3e molecule/mol',N0)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/10-Second_law_of_thermodynamics.ipynb b/Physical_Chemistry_by_G_H_Duffey/10-Second_law_of_thermodynamics.ipynb
new file mode 100644
index 0000000..ee3c699
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/10-Second_law_of_thermodynamics.ipynb
@@ -0,0 +1,168 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 10: Second law of thermodynamics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T2=100+273.2 //K\n",
+"T1=50+273.2 //K\n",
+"n=1 //mol\n",
+"R=1.987 //cal/deg mol\n",
+"//calculations\n",
+"dS=5/2 *n*R*2.303*log10(T2/T1)\n",
+"//results\n",
+"printf('Change in entropy = %.3f eu',dS)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"H=380 //cal\n",
+"T=273.2+32.1 //K\n",
+"//calculations\n",
+"dS=H/T\n",
+"//results\n",
+"printf('Entropy change = %.2f eu',dS)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Ha=0\n",
+"Hb=0\n",
+"//calculations\n",
+"H=Ha+Hb\n",
+"q=H\n",
+"U=0\n",
+"w=q-H\n",
+"//results\n",
+"printf('Work done = %d',w)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"prob=0.001\n",
+"R=1\n",
+"N=6.023*10^23\n",
+"//calculations\n",
+"dS=1.987*2.303*log10(prob) /N\n",
+"//results\n",
+"printf('change in entropy = %.1e eu',dS)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T=373.2 //K\n",
+"c=1.987 //cal/deg\n",
+"//calculations\n",
+"w=c*T\n",
+"A=-w\n",
+"//results\n",
+"printf('Change in A = %d cal',A)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/11-Condensed_phases.ipynb b/Physical_Chemistry_by_G_H_Duffey/11-Condensed_phases.ipynb
new file mode 100644
index 0000000..0a58c0d
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/11-Condensed_phases.ipynb
@@ -0,0 +1,87 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 11: Condensed phases"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"A=7.6546\n",
+"B=1686.8\n",
+"T=60+273.2\n",
+"//calculations\n",
+"logP=A-B/T\n",
+"P=10^logP\n",
+"//results\n",
+"printf('Vapor Pressure = %d mm',P+1)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"alpha=4.92*10^-5 //deg^-1\n",
+"beta=7.85*10^-7 //atm^-1\n",
+"d=8.93 //g/cm^3\n",
+"T=298.15 //K\n",
+"//calculations\n",
+"dC=63.54*T*alpha^2 *1.987/(d*beta*82.06)\n",
+"//results\n",
+"printf('Change in c values = %.3f cal/deg mol',dC)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/12-Physical_Equilibria.ipynb b/Physical_Chemistry_by_G_H_Duffey/12-Physical_Equilibria.ipynb
new file mode 100644
index 0000000..7480c5b
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/12-Physical_Equilibria.ipynb
@@ -0,0 +1,284 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 12: Physical Equilibria"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"p=3\n",
+"c=2\n",
+"//calculations\n",
+"f=2-p+c\n",
+"//results\n",
+"printf('no. of degrees of freedom = %d ',f)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T=273.2 //K\n",
+"vw=1.0001 //cm^3 /g\n",
+"vi=1.0907 //cm^3 /g\n",
+"hf=79.7 //cal/g\n",
+"P1=76 //cm\n",
+"P2=4.6 //cm\n",
+"//calculations\n",
+"dT=T*(vw-vi)*(P2-P1)*13.6*980.7/(hf*4.184*10^7)\n",
+"//results\n",
+"printf('change in temperature = %.4f deg',dT)\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"V=6.84 //cm^3 /g\n",
+"//calculations\n",
+"dPbydT=-1.7*4.184*10^7 /(2.19*V*0.06*1.01*10^6)\n",
+"//results\n",
+"printf('dPbydT = %d atm/deg',dPbydT)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P=6  //atm\n",
+"T=273.2+25 //K\n",
+"P=23.8 //mm\n",
+"V=0.018 //lt/mol\n",
+"R=0.08206 //lt am/deg mol\n",
+"//calculations\n",
+"dPa=V*P*4536/(R*T*760)\n",
+"Pa=dPa+P\n",
+"//results\n",
+"printf('Pressure = %.1f mm',Pa)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"x=0.25\n",
+"Ps1=96 //mm\n",
+"Ps2=43.9 //mm\n",
+"//calculations\n",
+"P1=x*Ps1\n",
+"P2=(1-x)*Ps2\n",
+"P=P1+P2\n",
+"Xdash=P1/P\n",
+"//results\n",
+"printf('mole fraction of methanol in vapor = %.3f ',Xdash)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Hv=539.6 //cal/g\n",
+"T=273.2+100 //K\n",
+"//calculations\n",
+"Kb=1.987*T^2 /(1000*Hv)\n",
+"//results\n",
+"printf('Molal elevation constant = %.3f deg /mole /kg',Kb)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"ms=0.5 //mol/kg\n",
+"m=5 //g\n",
+"mw=100 //g\n",
+"Ws=1000 //g/kg\n",
+"//calculations\n",
+"Ma=m*Ws/(ms*mw)\n",
+"//results\n",
+"printf('Molecular weight of solute = %d g/mol ',Ma)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.8: Example_8.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"dT=0.23 //C\n",
+"Kb=1.86 //deg/mol/kg\n",
+"//calculations\n",
+"m=dT/Kb\n",
+"//results\n",
+"printf('molality of solution = %.2f m',m)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"p=0.1 //m\n",
+"T=30+273.2  //K\n",
+"R=0.08206 //lt atm /deg/mol\n",
+"P1=1 //atm\n",
+"//calculations\n",
+"w=1000/p\n",
+"V=w/1000\n",
+"dP=R*T/V\n",
+"P=dP+P1\n",
+"//results\n",
+"printf('Osmotic Pressure =%.2f atm ',P)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/13-Thermodynamic_changes_accompanying_chemical_reaction.ipynb b/Physical_Chemistry_by_G_H_Duffey/13-Thermodynamic_changes_accompanying_chemical_reaction.ipynb
new file mode 100644
index 0000000..9dd2b33
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/13-Thermodynamic_changes_accompanying_chemical_reaction.ipynb
@@ -0,0 +1,323 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 13: Thermodynamic changes accompanying chemical reaction"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.10: Example_10.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"x=0.5\n",
+"P=0.468 //atm\n",
+"//calculations\n",
+"P1=x*P\n",
+"P2=x*P\n",
+"Kp=P1*P2\n",
+"//results\n",
+"printf('Final pressure after quilibrium = %.4f atm^2',Kp)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"n1=10 //mol\n",
+"n2=12 //mol\n",
+"//calculations\n",
+"dn=n1-n2\n",
+"//results\n",
+"printf('dHp = dEv- %d *RT',dn)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Ht1=-22063 //cal\n",
+"T=298.15 //K\n",
+"//calculations\n",
+"H=Ht1 +0.5293*T + 0.3398*10^-3 *T^2 - 2.039*10^-7 *T^3\n",
+"//results\n",
+"printf('Enthalpy = %d cal',H)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Cp=0.797 //cal/deg/mol\n",
+"//calculations\n",
+"S=Cp/3\n",
+"//results\n",
+"printf('Entropy = %.3f eu/mol',S)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T1=77.32 //K\n",
+"P=1 //atm\n",
+"T2=126 //K\n",
+"Pc=33.5 //atm\n",
+"//calculations\n",
+"dS=27/32 *1.987*P/Pc *(T2/T1)^3\n",
+"//results\n",
+"printf('Change in entropy = %.2f eu/mol',dS)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"S1=57.47\n",
+"S2=50.34\n",
+"S3=49\n",
+"H1=8.09\n",
+"H2=21.06\n",
+"H3=0\n",
+"F1=12.39\n",
+"F2=20.72\n",
+"F3=0\n",
+"//calculations\n",
+"dS=S1-S2-0.5*S3\n",
+"dH=H1-H2-0.5*H3\n",
+"dF=F1-F2-0.5*F3\n",
+"//results\n",
+"printf('Change in entropy = %.2f eu',dS)\n",
+"printf('\n Change in enthalpy = %.2f kcal',dH)\n",
+"printf('\n Change in free energy = %.2f kcal',dF)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P1=0.01\n",
+"P2=0.1\n",
+"P3=0.01\n",
+"dF0=-54640 //cal\n",
+"T=298.15 //K\n",
+"R=1.987 //cal/deg\n",
+"//calculations\n",
+"Qp=P1/(P2*P3^0.5)\n",
+"dF=dF0+R*T*log(Qp)\n",
+"//results\n",
+"printf('change in free energy = %d cal',dF)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"disp('From table 13.4 ')\n",
+"logKfwater=40.04724\n",
+"logKfH2=0\n",
+"logKfO2=0\n",
+"//calculations\n",
+"logK=logKfwater-logKfH2-0.5*logKfO2\n",
+"K=10^logK\n",
+"//results\n",
+"printf('Equilibrium constant = %.4e',K)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.8: Example_8.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Kp=1.1*10^40 //atm^-0.5\n",
+"dn=-0.5\n",
+"R=0.08206 //lt atm/deg mol\n",
+"T=298.15 //K\n",
+"//calculations\n",
+"Kc=Kp*(R*T)^(-dn)\n",
+"//results\n",
+"printf('Kc = %.1e (mol/lt)^-0.5',Kc)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 13.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Kp=0.141 //atm\n",
+"P=1 //atm\n",
+"nu=2\n",
+"R=0.08206 //lt atm/deg mol\n",
+"T=298.15 //K\n",
+"M=92.02 //g/mol\n",
+"//calculations\n",
+"a=poly(0,'a');\n",
+"p=Kp*a^2 +4*a^2*P -Kp\n",
+"z=roots(p)\n",
+"alpha=z(1)\n",
+"wbyV=P*M/(R*T*(1+(nu-1)*alpha))\n",
+"//results\n",
+"printf('Density of the equilibrium mixture = %.2f g/lt',wbyV)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/14-Development_and_use_of_activity_concepts.ipynb b/Physical_Chemistry_by_G_H_Duffey/14-Development_and_use_of_activity_concepts.ipynb
new file mode 100644
index 0000000..c1f94b0
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/14-Development_and_use_of_activity_concepts.ipynb
@@ -0,0 +1,470 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 14: Development and use of activity concepts"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.10: Example_10.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"m1=0.1 //m\n",
+"m2=0.1 //m\n",
+"K=1.754*10^-5 //m\n",
+"//calculations\n",
+"mu=0.5*(m1*1^2 + m2*1^2)\n",
+"disp('From table 14.5,')\n",
+"aH=9 //A\n",
+"aA=4.5 //A\n",
+"disp('From table 14.6')\n",
+"gH=0.825\n",
+"gA=0.775\n",
+"gHA=1\n",
+"x1=gHA*K/(gH*gA)\n",
+"disp('Assuming x to be small w.r.t m1,')\n",
+"x=sqrt(x1*m1)\n",
+"//results\n",
+"printf('Concentration of H plus ions = %.2e m',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.11: Example_11.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"K=1.754*10^-5 //m\n",
+"c=0.1\n",
+"//calculations\n",
+"disp('Neglecting x w.r.t c,')\n",
+"x2=K\n",
+"x=sqrt(K)\n",
+"mu=x\n",
+"disp('From tables 14-5 and 14-6,')\n",
+"gH=0.963\n",
+"gA=0.960\n",
+"x22=K/(gH*gA)\n",
+"a=poly(0,'a');\n",
+"p=a^2 +a*x22 -c*x22\n",
+"z=roots(p)\n",
+"alpha=z(2)\n",
+"//results\n",
+"printf('concentration of H plus ions = %.2e m',alpha)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.12: Example_12.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"disp('From table 14.3')\n",
+"K1=-13.5089\n",
+"K2=-22.9792\n",
+"K3=19.2218\n",
+"c=0.1 //m\n",
+"//calculations\n",
+"logK=K1-K2-K3\n",
+"K=10^logK\n",
+"mu=0.5*(c*1^2 + c*1^2)\n",
+"disp('From tables 14-5 and 14-6,')\n",
+"gAg=0.745\n",
+"gCl=0.755\n",
+"x2=K/(gAg*gCl)\n",
+"x=sqrt(x2)\n",
+"//results\n",
+"printf('Solubility of Agcl = %.2e m',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.13: Example_13.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Cna=0.11\n",
+"Ccl=0.1\n",
+"//calculations\n",
+"x=poly(0,'x');\n",
+"p=99*x^2 - 2.1*x+Cna*Ccl\n",
+"z=roots(p)\n",
+"alpha=z(2)\n",
+"Na1=Cna-10*alpha\n",
+"Cl1=Ccl-10*alpha\n",
+"//results\n",
+"printf(' Concentration of Na in 1  = %.4f M',Na1)\n",
+"printf('\n Concentration of Cl in 1  = %.4f M',Cl1)\n",
+"printf('\n Concentration of Na in 2  = %.4f M',alpha)\n",
+"printf('\n Concentration of Cl in 2  = %.4f M',alpha)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"x1=0.0200\n",
+"Kx=812\n",
+"//calculations\n",
+"disp('Neglecting 2x in comparision with x1,')\n",
+"x=x1/Kx\n",
+"//results\n",
+"printf('Moles of Iodine present = %.2e mole',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Kc=1.749*10^-5 //M\n",
+"n1=0.1 //mole\n",
+"n2=0.01 //mole\n",
+"//calculations\n",
+"c=n1/n2 *Kc\n",
+"//results\n",
+"printf('Concentration of Hplus ions = %.1e M',c)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=0.01 //M\n",
+"kc=1.749*10^-5 //M\n",
+"//calculations\n",
+"x2=c*kc\n",
+"x=sqrt(x2)\n",
+"//results\n",
+"printf('Concentraton of Hplus ions = %.1e M',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"K2=1.0008*10^-14 //m^2\n",
+"K1=1.754*10^-5 //m\n",
+"c=0.1\n",
+"//calculations\n",
+"disp('Neglecting x w.r.t c,')\n",
+"x2=c*K2/K1\n",
+"x=sqrt(x2)\n",
+"//results\n",
+"printf('Concentration of OH minus ions = %.1e m',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"disp('from table 14.1,')\n",
+"r1=7.47*10^-5 //m\n",
+"r2=4.57*10^-3 //m\n",
+"mp=1.008*10^-14 //m^2\n",
+"//calculations\n",
+"r3=r2/r1\n",
+"mH2=r3*mp\n",
+"mH=sqrt(mH2)\n",
+"//results\n",
+"printf('Concentraton of Hplus ions = %.2e M',mH)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"disp('from table 14.1,')\n",
+"r1=1.75*10^-5 //m\n",
+"r2=1.772*10^-4 //m\n",
+"mp=1.008*10^-14 //m^2\n",
+"//calculations\n",
+"r3=r2/r1\n",
+"mH2=r3*mp\n",
+"mH=sqrt(mH2)\n",
+"//results\n",
+"printf('Concentraton of Hplus ions = %.1e M',mH)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.7: example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=1*10^-6 //m\n",
+"K=1.754*10^-5 //m\n",
+"Kp=1.008*10^-14 //m^2\n",
+"//calculations\n",
+"mH=c\n",
+"//Iteration 1\n",
+"mOH=Kp/mH\n",
+"mA=mH-mOH\n",
+"mHA=mH*mA/K\n",
+"mH2=mH-mHA+mOH\n",
+"//Iteration 2\n",
+"mOH2=Kp/mH2\n",
+"mA2=mH2-mOH2\n",
+"mHA2=mH2*mA2/K\n",
+"mH3=mH2-mHA2+mOH2\n",
+"//From x2\n",
+"x2=sqrt(Kp)\n",
+"x1=c\n",
+"mOH3=Kp/x2\n",
+"y2=x1\n",
+"//From x1\n",
+"mOH4=Kp/c\n",
+"mA4=mH-mOH4\n",
+"mHA4=mH*mA4/K\n",
+"y1=c-mHA4-mA4\n",
+"//upon further iterations, we get\n",
+"mHplus=mH3\n",
+"//results\n",
+"printf('Concentration of H plus ions = %.2e m',mHplus)\n",
+"//The answer is a bit different due to rounding off error."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.8: Example_8.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variableH\n",
+"disp('From table 14-3,')\n",
+"HH=0\n",
+"HHcoo=-98\n",
+"HHcooh=-98\n",
+"SH=0\n",
+"SHcoo=21.9\n",
+"SHcooh=39.1\n",
+"KH=0\n",
+"KHcoo=58.64\n",
+"KHcooh=62.38\n",
+"//calculationH\n",
+"dH=HH+HHcoo-HHcooh\n",
+"dS=SH+SHcoo-SHcooh\n",
+"dK=KH+KHcoo-KHcooh\n",
+"K=10^dK\n",
+"//results\n",
+"printf(' dS0 = %.1f eu',dS)\n",
+"printf('\n dH0 = %.1f kcal',dH)\n",
+"printf('\n log Krm = %.2f ',dK)\n",
+"printf('\n Krm = %.1e m',K)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 14.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"mca=0.01 //m\n",
+"mcl=0.02 //m\n",
+"//calculations\n",
+"Mu=0.5*(mca*4 + mcl*1)\n",
+"disp('From table 14-5,')\n",
+"aca=6 //A\n",
+"acl=3 //A\n",
+"disp('From table 14-6,')\n",
+"gaca=0.555 \n",
+"gacl=0.843\n",
+"Aca=gaca*mca\n",
+"Acl=gacl*mcl\n",
+"//results\n",
+"printf('Activity of cl = %.4f ',Acl)\n",
+"printf('\n Activity of ca = %.4f ',Aca)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/15-Electrochemistry.ipynb b/Physical_Chemistry_by_G_H_Duffey/15-Electrochemistry.ipynb
new file mode 100644
index 0000000..6f7d74c
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/15-Electrochemistry.ipynb
@@ -0,0 +1,236 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 15: Electrochemistry"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"I=0.5 //amp\n",
+"t=55  //min\n",
+"we=31.77\n",
+"//calculations\n",
+"Q=I*t*60\n",
+"n=Q/96496\n",
+"w=n*we\n",
+"//results\n",
+"printf('Weight of copper leaving = %.3f g',w)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"w1=0.7532 //g\n",
+"w2=0.9972 //g\n",
+"wdep=0.4 //g\n",
+"we=31.77 //g\n",
+"//calculations\n",
+"dn=w2/we - w1/we\n",
+"t=dn/(wdep/we)\n",
+"dne=wdep/we\n",
+"dnmig=dn-dne\n",
+"tplus=-dnmig/dne\n",
+"tminus=1-tplus\n",
+"//results\n",
+"printf('tplus = %.3f',tplus)\n",
+"printf('\n tminus= %.3f',tminus)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"R1=312 //ohms\n",
+"R2=1043 //ohms\n",
+"c=0.01 //N\n",
+"kdash=0.002768 //ohm^-1cm^-1\n",
+"//calculations\n",
+"k=kdash*R1\n",
+"kdash2=k/R2\n",
+"lambda=kdash2/(c/1000)\n",
+"//results\n",
+"printf('Equivalent conductance = %.1f ohm^-1 cm^2 equiv^-1',lambda)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"l1=349.8 \n",
+"l2=40.9\n",
+"//calculations\n",
+"l=l1+l2\n",
+"//results\n",
+"printf('Conductance for acetic acid = %.1f ohm^-1 cm^2',l)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"l1=63.6\n",
+"l2=79.8\n",
+"n=1 //mg/lt\n",
+"we=116.7 //g/equiv\n",
+"//calculations\n",
+"l=l1+l2\n",
+"c=n*10^-3 /we\n",
+"k=c*l/1000\n",
+"//results\n",
+"printf('Specific conductance = %.2e ohm^-1 cm^-1',k)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"e1=0.763 //volt\n",
+"e2=0.337 //volt\n",
+"//calculations\n",
+"e0=e1+e2\n",
+"//results\n",
+"printf('Standard electrode potential of the cell = %.3f volts',e0)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 15.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"aZn=0.1\n",
+"aCu=0.01\n",
+"e1=0.763 //volt\n",
+"e2=0.337 //volt\n",
+"//calculations\n",
+"e0=e1+e2\n",
+"Q=aZn/aCu\n",
+"E=e0- 0.05915*log10(Q) /2\n",
+"//results\n",
+"printf('Emf of the cell = %.3f volts',E)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/16-Typical_mechanisms_and_rate_laws.ipynb b/Physical_Chemistry_by_G_H_Duffey/16-Typical_mechanisms_and_rate_laws.ipynb
new file mode 100644
index 0000000..8b9411f
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/16-Typical_mechanisms_and_rate_laws.ipynb
@@ -0,0 +1,111 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 16: Typical mechanisms and rate laws"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 16.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P1=69.2 //mm\n",
+"P2=39.8//mm\n",
+"t=20 //min\n",
+"//calculations\n",
+"k=2.303*log10(P1/P2) /(t*60)\n",
+"//results\n",
+"printf('Rate constant = %.2e sec^-1',k)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 16.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"t=10 //min\n",
+"x=90\n",
+"//calculations\n",
+"k=2.303*log10(100/(100-x)) /t\n",
+"//results\n",
+"printf('Rate constant = %.3f min^-1',k)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 16.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"t=242 //sec\n",
+"P=229 //mm\n",
+"P0=363 //mm\n",
+"//calculations\n",
+"k=(1/P -1/P0)/t\n",
+"//results\n",
+"printf('rate constant= %.2e sec^-1 mm^-1',k)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/17-Resolving_Kinetic_data.ipynb b/Physical_Chemistry_by_G_H_Duffey/17-Resolving_Kinetic_data.ipynb
new file mode 100644
index 0000000..ae23630
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/17-Resolving_Kinetic_data.ipynb
@@ -0,0 +1,152 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 17: Resolving Kinetic data"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 17.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variablesx1=5\n",
+"x2=20\n",
+"x1=5\n",
+"n1=7.49\n",
+"n2=5.14\n",
+"//calculations\n",
+"n=(log(n1)-log(n2))/(log(100-x1) - log(100-x2))\n",
+"//results\n",
+"printf('Order of the reaction  = %.2f',n)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 17.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"p2=169\n",
+"p1=363\n",
+"t1=410\n",
+"t2=880\n",
+"//calculations\n",
+"ndash=(log(t2) - log(t1))/(log(p1) - log(p2))\n",
+"n=ndash+1\n",
+"//results\n",
+"printf('Order of the reaction = %.2f',n)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 17.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"R=1.987 //cal/deg/mol\n",
+"k1=4.45*10^-5\n",
+"k2=2.52*10^-6\n",
+"T1=283+273.2 //K\n",
+"T2=356+273.2 //K\n",
+"//calculations\n",
+"Ea=2.303*R*1.7530 /(1/T1 - 1/T2)\n",
+"logZ= log10(k1) +Ea/(2.303*R*T1)\n",
+"Z=10^logZ\n",
+"//results\n",
+"printf('Activation energy = %d cal/mol',Ea)\n",
+"printf('\n Z = %.1e lt /mol sec',Z)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 17.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"g1=0.661\n",
+"g2=0.899\n",
+"g3=0.405\n",
+"g4=0.803\n",
+"g5=0.946\n",
+"g6=0.614\n",
+"k=1.33\n",
+"//calculations\n",
+"k0=k*g3/(g1*g2)\n",
+"k2=k0*g4*g5/g6\n",
+"//results\n",
+"printf('Equlibrium constant = %.2f lt/mol min',k2)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/18-Catalysis.ipynb b/Physical_Chemistry_by_G_H_Duffey/18-Catalysis.ipynb
new file mode 100644
index 0000000..2c3c7a0
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/18-Catalysis.ipynb
@@ -0,0 +1,93 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 18: Catalysis"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 18.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"V1=0.284 //cm^3 /g\n",
+"V2=1.43 //cm^3 /g\n",
+"P1=142.4 //mm\n",
+"P2=760 //mm\n",
+"//calculations\n",
+"z=(1/V1 - 1/V2)/(1/P1 - 1/P2)\n",
+"invVm=1/V2 - z/P2\n",
+"Vm=1/invVm\n",
+"//results\n",
+"printf('Volume = %.1f cm^3/g',Vm)\n",
+"//The answer in the textbook is a bit different due to rounding off error."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 18.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"Vm=2.86 //cc/g\n",
+"P=1 //atm\n",
+"R=82.06 //cm^3 atm/deg mol\n",
+"T=273.2 //deg\n",
+"N=6.023*10^23\n",
+"sigma=16.2*10^-16 //cm^2 /molecule\n",
+"//calculations\n",
+"n=P*Vm/(R*T)\n",
+"A=N*n*sigma\n",
+"//results\n",
+"printf('total area = %.2e cm^2 (g catalyst)^-1',A)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/19-Photochemistry.ipynb b/Physical_Chemistry_by_G_H_Duffey/19-Photochemistry.ipynb
new file mode 100644
index 0000000..6072349
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/19-Photochemistry.ipynb
@@ -0,0 +1,287 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 19: Photochemistry"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"r1=0.727\n",
+"r2=0.407\n",
+"//calculations\n",
+"r3=r1*r2\n",
+"//results\n",
+"printf('Overall transmittance = %.3f',r3)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"r=0.450\n",
+"c=0.02 //M\n",
+"l=4 //cm\n",
+"//calculations\n",
+"e=-log10(r) /(c*l)\n",
+"//results\n",
+"printf('Extinction coefficient = %.2f litres mole^-1 cm^-1',e)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"r1=0.850\n",
+"r2=0.50\n",
+"//calculations\n",
+"Da=-log10(r1)\n",
+"Db=-log10(r2)\n",
+"D=Da+Db\n",
+"r3=10^(-D)\n",
+"//results\n",
+"printf('Transmittance of solution = %.3f ',r3)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=0.000025 //M\n",
+"l=2 //cm\n",
+"D=0.417\n",
+"//calculations\n",
+"e=D/(c*l)\n",
+"//result\n",
+"printf('Extinction coefficient = %d liters mole^-1 cm^-1',e)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=0.5 //M\n",
+"c1=0.000025 //M\n",
+"D2=0.280\n",
+"D1=0.417\n",
+"//calculations\n",
+"c2=D2*c1/(D1)\n",
+"dC=c1-c2\n",
+"SCN=c- 6*c2 -4*dC\n",
+"K=dC*SCN^2 /c2\n",
+"//results\n",
+"printf('Kc for dissociation = %.2f M^2',K)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"D2=0.249\n",
+"D1=0.172\n",
+"a2=0.00752\n",
+"a1=0.00527\n",
+"//calculations\n",
+"m=(log(D2) -log(D1))/(log(a2) - log(a1))\n",
+"//results\n",
+"printf('m = %.2f ',m)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=0.1 //M\n",
+"V=100 //ml\n",
+"v1=25 //ml\n",
+"D=0.980\n",
+"d1=0.090\n",
+"d2=0.150\n",
+"//calculations\n",
+"a=v1*c/V\n",
+"b=(V-v1)*c/V\n",
+"Da=a*d1/c\n",
+"Db=b*d2/c\n",
+"Ddash=Da+Db\n",
+"dD=D-Ddash\n",
+"//results\n",
+"printf('Increase in optical density = %.3f',dD)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.8: Example_8.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"E=50000 //cal/mol\n",
+"//calculations\n",
+"lam=2.8593/E\n",
+"//results\n",
+"printf('For the reaction to occur lambda < %d A',lam*10^8)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 19.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"lam=3000*10^-8 //cm\n",
+"yield=0.420\n",
+"Et=70000 //cal\n",
+"//calculations\n",
+"E=2.8593/lam\n",
+"n=yield*Et/E\n",
+"//results\n",
+"printf('Amount of reactant disappeared = %.3f mol',n)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/2-Particles_Atomic_and_subatomic.ipynb b/Physical_Chemistry_by_G_H_Duffey/2-Particles_Atomic_and_subatomic.ipynb
new file mode 100644
index 0000000..86b9e17
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/2-Particles_Atomic_and_subatomic.ipynb
@@ -0,0 +1,146 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 2: Particles Atomic and subatomic"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"m1=1.008142\n",
+"m2=1.008982\n",
+"//calculations\n",
+"dm=m1-m2\n",
+"dt=abs(dm) *931\n",
+"//results\n",
+"printf('Increase in kinetic energy = %.3f Mev',dt)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"d=8.642 //g/cc\n",
+"M=112.41 //g/mol\n",
+"ratio=0.01/100\n",
+"nb=2400\n",
+"//calculations\n",
+"n=d*6.02*10^23 /M\n",
+"sigma=nb*10^-24\n",
+"x=-2.303*log10(ratio) /(sigma*n)\n",
+"//results\n",
+"printf('Thickness = %.3f cm',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"M1=4\n",
+"M2=14\n",
+"E=-1.2 //Mev\n",
+"//calculations\n",
+"R1=1.5*10^-13 *(M1)^(1/3)\n",
+"R2=1.5*10^-13 *(M2)^(1/3)\n",
+"V1=2*7*(4.8*10^-10)^2 /(R1+R2)\n",
+"V2=V1/(1.6*10^-6)\n",
+"x=(M1+M2)*V2/M2\n",
+"//results\n",
+"printf('Threshold = %.1f Mev',x)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"t=1622 //years\n",
+"per=1 //percent\n",
+"//calculations\n",
+"Nratio=1-per/100\n",
+"x=t*log10(Nratio) / log10(0.5)\n",
+"//results\n",
+"printf('Time taken = %.1f years',x)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/3-Waves_and_Quanta.ipynb b/Physical_Chemistry_by_G_H_Duffey/3-Waves_and_Quanta.ipynb
new file mode 100644
index 0000000..ab8c088
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/3-Waves_and_Quanta.ipynb
@@ -0,0 +1,57 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 3: Waves and Quanta"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"atoms=5\n",
+"//calculations\n",
+"f=3*atoms\n",
+"fvib=f-3-3\n",
+"//results\n",
+"printf('Vibrational degrees of freedom = %d',fvib)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/4-Molecular_energy_levels.ipynb b/Physical_Chemistry_by_G_H_Duffey/4-Molecular_energy_levels.ipynb
new file mode 100644
index 0000000..0539393
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/4-Molecular_energy_levels.ipynb
@@ -0,0 +1,143 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 4: Molecular energy levels"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"B=10.34 //cm^-1\n",
+"c=2.998*10^10 //cm/s\n",
+"h=6.625*10^-27 //erg sec\n",
+"//calculations\n",
+"I=h/(8*%pi^2 *B*c)\n",
+"//results\n",
+"printf('Moment of inertia = %.2e g cm^2',I)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"ma=1.0080\n",
+"mb=35.457\n",
+"Na=6.0232*10^23\n",
+"I=2.707*10^-40 //g cm^2\n",
+"//calculations\n",
+"mu1=ma*mb/(ma+mb)\n",
+"mu2=mu1/Na\n",
+"r=sqrt(I/mu2)\n",
+"//results\n",
+"printf('Bond length = %.2e cm',r)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"c=2.998*10^10 //cm/s\n",
+"wave=2990 //cm^-1\n",
+"mu=1.627*10^-24 //g\n",
+"//calculations\n",
+"k=mu*(2*%pi*c*wave)^2\n",
+"//results\n",
+"printf('Force constant = %.2e dynes/cm',k)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"l1=2886 //cm^-1\n",
+"l2=5668 //cm^-1\n",
+"//calculations\n",
+"wave=2*l1-l2 \n",
+"wave2= wave+l1\n",
+"x=wave/(2*wave2)\n",
+"//results\n",
+"printf('anharmonicity constant = %.4f ',x)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/6-Valence_electrons_in_molecules.ipynb b/Physical_Chemistry_by_G_H_Duffey/6-Valence_electrons_in_molecules.ipynb
new file mode 100644
index 0000000..99525e9
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/6-Valence_electrons_in_molecules.ipynb
@@ -0,0 +1,187 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 6: Valence electrons in molecules"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.10: Example_10.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"DHH=42 //kcal/mol\n",
+"//calculations\n",
+"DHHp=0.5*(DHH)\n",
+"//results\n",
+"printf('Exchange energy = %.1f kcal/mol',DHHp)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"a2=1/8\n",
+"//calculations\n",
+"b2=1-a2\n",
+"a1=sqrt(a2)\n",
+"b1=sqrt(b2)\n",
+"//results\n",
+"printf(' Wave function is %.2f phi1 +%.2f phi2',a1,b1)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"sinu=2/sqrt(3)\n",
+"cosu=sqrt(2/3)\n",
+"//calculations\n",
+"tanu=sinu/cosu\n",
+"u=atand(sinu/cosu)\n",
+"//results\n",
+"printf('Bond anagle = %.2f degrees',2*u)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"cosu=1/sqrt(3)\n",
+"sinu=sqrt(2/3)\n",
+"//calculations\n",
+"f=1/2 + sqrt(3) /2 *cosu + sqrt(3/2) *sinu\n",
+"//results\n",
+"printf('Pauling strength = %d ',f)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"alpha=60\n",
+"//calculations\n",
+"cosa=cosd(alpha)\n",
+"sina=sind(alpha)\n",
+"//results\n",
+"printf('Wave function  = %.2f s + %.2f pz',cosa,sina)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.9: Example_9.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//initialization of variables\n",
+"DHH=103 //kcal/mol\n",
+"//calculations\n",
+"DHHp=0.5*(DHH)\n",
+"//results\n",
+"printf('Bond energy = %.1f kcal/mol',DHHp)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/7-Gases_and_Introductory_stastical_thermodynamics.ipynb b/Physical_Chemistry_by_G_H_Duffey/7-Gases_and_Introductory_stastical_thermodynamics.ipynb
new file mode 100644
index 0000000..cf16198
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/7-Gases_and_Introductory_stastical_thermodynamics.ipynb
@@ -0,0 +1,243 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 7: Gases and Introductory stastical thermodynamics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"h=76 //cm\n",
+"d=13.5951 //g/cc\n",
+"g=980.655 //cm/s^2\n",
+"T=273.15 //K\n",
+"v=22414.6 //cm^3 /mol\n",
+"//calculations\n",
+"P=h*d*g\n",
+"R=P*v/(T)\n",
+"//results\n",
+"printf('Gas constant = %.3e ergs/deg. mol',R)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"cal=4.184*10^7 //ergs\n",
+"R=8.315*10^7 //ergs/deg/mol\n",
+"//calculations\n",
+"Rdash=R/cal\n",
+"//results\n",
+"printf('R in calories = %.3f cal/ deg mol',Rdash)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"R=8.315*10^7 //ergs/deg/mol\n",
+"T=273.2 //deg\n",
+"M=4 //g/mol\n",
+"//calculations\n",
+"u2=3*T*R/M\n",
+"u=sqrt(u2)\n",
+"//results\n",
+"printf('root mean square velocity = %.2e cm/sec',u)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"n1=2\n",
+"n2=10\n",
+"n3=3\n",
+"P=720 //mm of Hg\n",
+"//calculations\n",
+"n=n1+n2+n3\n",
+"x1=n1/n\n",
+"P1=x1*P\n",
+"x2=n2/n\n",
+"P2=x2*P\n",
+"x3=n3/n\n",
+"P3=x3*P\n",
+"//results\n",
+"printf('\n Partial pressure of N2 = %d mm',P1)\n",
+"printf('\n Partial pressure of O2 = %d mm',P2)\n",
+"printf('\n Partial pressure of CO2 = %d mm',P3)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.6: Example_6.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T=273.2+25 //K\n",
+"n=1 //mol\n",
+"R=1.987 //cal/deg mol\n",
+"//calculations\n",
+"Etr=1.5*n*R*T\n",
+"Erot=1.5*n*R*T\n",
+"Evib=0\n",
+"Eel=0\n",
+"Etot=Etr+Erot+Evib+Eel\n",
+"//results\n",
+"printf('Total energy = %d cal',Etot)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.7: Example_7.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"b=24.1 //cm^2/mol\n",
+"N=6.023*10^23 //mole^-1\n",
+"//calculations\n",
+"d=(3*b/(2*%pi*N))^(1/3)\n",
+"//results\n",
+"printf('Molecular diameter of He = %.2e cm',d)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.8: Example_8.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P=100 //atm\n",
+"T=200 //K\n",
+"n=1 //mole\n",
+"R=0.08206 //l atm/deg mol\n",
+"disp('From psychrometric charts,')\n",
+"Tc=126.2 //K\n",
+"Pc=33.5 //K\n",
+"//calculations\n",
+"Pr=P/Pc\n",
+"Tr=T/Tc\n",
+"disp('From z charts,')\n",
+"z=0.83\n",
+"V=z*n*R*T/P\n",
+"//results\n",
+"printf('Volume = %.3f liter',V)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/8-First_law_of_thermodynamics.ipynb b/Physical_Chemistry_by_G_H_Duffey/8-First_law_of_thermodynamics.ipynb
new file mode 100644
index 0000000..e75b11a
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/8-First_law_of_thermodynamics.ipynb
@@ -0,0 +1,177 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 8: First law of thermodynamics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P=1.0132*10^6 //dynes/cm^2\n",
+"A=100 //cm^2\n",
+"z=10 //cm\n",
+"//calculations\n",
+"w=P*A*z*10^-7\n",
+"//results\n",
+"printf('Joules = %.4e J',w)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"P=1.0132*10^6 //dynes/cm^2\n",
+"A=100 //cm^2\n",
+"z=10 //cm\n",
+"//calculations\n",
+"w=P*A*z*10^-7\n",
+"cal=w/4.184\n",
+"//results\n",
+"printf('Calories = %.3f cal',cal)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.3: Example_3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T=373.2 //K\n",
+"n=1 //mol\n",
+"qp=9720 //cal/mol\n",
+"//calculations\n",
+"q=n*qp\n",
+"w=1.987*T\n",
+"dE=q-w\n",
+"//results\n",
+"printf('Heat of vaporization = %d cal',q)\n",
+"printf('\n Change in energy = %d cal',dE)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.4: Example_4.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"T1=25+273 //K\n",
+"T2=25+273 //K\n",
+"//calculations\n",
+"disp('Since, T2=T1, dE=0')\n",
+"dE=0\n",
+"w=0\n",
+"q=dE+w\n",
+"//results\n",
+"printf('\n Work done = %d ',w)\n",
+"printf('\n Heat transferred = %d ',q)\n",
+"printf('\n Change in energy = %d',dE)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.5: Example_5.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"R=1.987 //cal/deg mol\n",
+"//calculations\n",
+"Cvtr=1.5*R\n",
+"Cvrot=1.5*R\n",
+"Cvt=Cvtr+Cvrot\n",
+"disp('Observed Cv= 6.43')\n",
+"Cvobs=6.43\n",
+"Cvvib=Cvobs-Cvt\n",
+"//results\n",
+"printf('Vibrational = %.2f cal/deg mol',Cvvib)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Physical_Chemistry_by_G_H_Duffey/9-Boltzmann_distribution_law.ipynb b/Physical_Chemistry_by_G_H_Duffey/9-Boltzmann_distribution_law.ipynb
new file mode 100644
index 0000000..fd8df12
--- /dev/null
+++ b/Physical_Chemistry_by_G_H_Duffey/9-Boltzmann_distribution_law.ipynb
@@ -0,0 +1,93 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 9: Boltzmann distribution law"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.1: Example_1.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"r=2.1*10^-6 //cm\n",
+"n=889\n",
+"x=0.1 //cm\n",
+"T=298.2 //K\n",
+"//calculations\n",
+"V=4/3 *%pi *r^3\n",
+"rho=19.3-1\n",
+"ffd=rho*V*980.7\n",
+"eps=ffd*x\n",
+"logN=-6.96*10^-14 /(2.303*1.38*10^-16 *T)\n",
+"N=10^logN *n\n",
+"//results\n",
+"printf('No. of particles = %d ',N+1)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.2: Example_2.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clc\n",
+"//Initialization of variables\n",
+"x=1 //percent\n",
+"wave=1595 //cm^-1\n",
+"//calculations\n",
+"E=2.8593*wave\n",
+"Nratio=(100-x)/x\n",
+"logN=log10(Nratio)\n",
+"T=E/(2.303*1.987*logN)\n",
+"//results\n",
+"printf('Temperature = %d K',T)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}