initial commit / add all books

97 files changed, 645 insertions, 418 deletions

diff --git a/3876/CH10/EX10.1/Ex10_1.sce b/3876/CH10/EX10.1/Ex10_1.sce
index 1f501a5a2..f9ca36487 100644
--- a/3876/CH10/EX10.1/Ex10_1.sce
+++ b/3876/CH10/EX10.1/Ex10_1.sce
@@ -1,17 +1,21 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
-M= 0.08 //m
-P= 1 //atm
-F= 96500 //coloumbs
-R= 8.31 //J/mol K
+T= 25 //temperature in Celsius
+M= 0.08 //activity of hydronium ions in m
+P= 1 //pressure in atm
+F= 96500 //charge in coloumbs
+R= 8.31 //in electrical units J/mol K
 
 //CALCULATIONS
-E= -R*(273+T)*2.3*log10(M)/F
+E_e1= -R*(273+T)*2.3*log10(M)/F
 
 //RESULTS
-mprintf("Oxidation potential of hydrogen electrode = %.3f v",E)
+mprintf("Oxidation potential of hydrogen electrode = %.3f v",E_e1)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH10/EX10.2/Ex10_2.sce b/3876/CH10/EX10.2/Ex10_2.sce
index f04006099..cdbf2dcea 100644
--- a/3876/CH10/EX10.2/Ex10_2.sce
+++ b/3876/CH10/EX10.2/Ex10_2.sce
@@ -1,17 +1,19 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= -0.337 //v
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
-M= 0.12 //m
+E_Cu_Cu2_plus= -0.337 //voltage of electrode
+R= 8.31 //in electrical units J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
+M= 0.12 //m in cupric ions
 
 //CALCULATIONS
-E1= E-(R*(273+T)*2.3*log10(M)/(2*F))
+E_e1= E_Cu_Cu2_plus-(R*(273+T)*2.3*log10(M)/(2*F))
 
 //RESULTS
-mprintf("Oxidation potential of copper electrode = %.3f v",E1)
+mprintf("Oxidation potential of copper electrode = %.3f v",E_e1)
diff --git a/3876/CH10/EX10.3/Ex10_3.sce b/3876/CH10/EX10.3/Ex10_3.sce
index 81d074e04..0ef8a9fd3 100644
--- a/3876/CH10/EX10.3/Ex10_3.sce
+++ b/3876/CH10/EX10.3/Ex10_3.sce
@@ -1,18 +1,20 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= -0.771 //v
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
-M= 0.02 //m
-M1= 0.1 //m
+E_e1= -0.771 //voltage
+R= 8.31 //in electrical units J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
+M= 0.02 //ferric ion activity in m
+M1= 0.1 //ferrous ion activity in m
 
 //CALCULATIONS
-E1= E-(R*(273+T)*2.3*log10(M/M1)/F)
+E1= E_e1-(R*(273+T)*2.3*log10(M/M1)/F)
 
 //RESULTS
 mprintf("Oxidation potential of copper electrode = %.2f v",E1)
diff --git a/3876/CH10/EX10.4/Ex10_4.sce b/3876/CH10/EX10.4/Ex10_4.sce
index c65ca17c1..7597a3ca4 100644
--- a/3876/CH10/EX10.4/Ex10_4.sce
+++ b/3876/CH10/EX10.4/Ex10_4.sce
@@ -1,18 +1,20 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= 0.763 //v
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
-M= 0.1 //m
-M1= 0.01 //m
+E= 0.763 //voltage in v
+R= 8.31 //in electrical unit J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
+M= 0.1 //ion activity in m
+M1= 0.01 //ion activity in m
 
 //CALCULATIONS
-E1= E-(R*(273+T)*2.3*log10(M)/(2*F))+R*(273+T)*2.3*log10(M1)/F
+E_cell= E-(R*(273+T)*2.3*log10(M)/(2*F))+R*(273+T)*2.3*log10(M1)/F
 
 //RESULTS
-mprintf("Oxidation potential of copper electrode = %.2f v",E1)
+mprintf("Oxidation potential of copper electrode = %.2f v",E_cell)
diff --git a/3876/CH10/EX10.5/Ex10_5.sce b/3876/CH10/EX10.5/Ex10_5.sce
index 31107e6cd..063e8e768 100644
--- a/3876/CH10/EX10.5/Ex10_5.sce
+++ b/3876/CH10/EX10.5/Ex10_5.sce
@@ -1,19 +1,21 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-E1= 0.126 //v
-E2= -1.360 //v
-M= 0.02 //m
-M1= 1/0.1 //m
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
+E_Pb_Pb2_plus= 0.126 //voltage in v
+E_Cl2_Cl_minus= -1.360 //voltage in v
+M= 0.02 //ion activity in m
+M1= 1/0.1 //ion activity in m
+R= 8.31 //in electrical units J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
 
 //CALCULATIONS
-E= (E1-R*(273+T)*2.3*log10(M)/(2*F))-(E2-R*(273+T)*2.3*log10(M1)/(F))
+E_cell= (E_Pb_Pb2_plus-R*(273+T)*2.3*log10(M)/(2*F))-(E_Cl2_Cl_minus-R*(273+T)*2.3*log10(M1)/(F))
 
 //RESULTS
-mprintf("Oxidation potential of copper electrode = %.3f v",E)
+mprintf("Oxidation potential of copper electrode = %.3f v",E_cell)
diff --git a/3876/CH10/EX10.6/Ex10_6.sce b/3876/CH10/EX10.6/Ex10_6.sce
index d384c46f1..a6c42d8b5 100644
--- a/3876/CH10/EX10.6/Ex10_6.sce
+++ b/3876/CH10/EX10.6/Ex10_6.sce
@@ -1,20 +1,22 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-E1= 0.763 //v
+E1= 0.763 //voltage
 c= 0.1 //mol/lit
 c1= 0.01 //mol/lit
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
+R= 8.31 //in electrical unit J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
 c2= 1 //molar
 c3= 1 //molar
 
 //CALCULATIONS
-E= E1-(log10(c*c2/(c1**2*c3))*R*(273+T)*2.3/(2*F))
+E_cell= E1-(log10(c*c2/(c1**2*c3))*R*(273+T)*2.3/(2*F))
 
 //RESULTS
-mprintf("Potential of the cell = %.3f v",E)
+mprintf("Potential of the cell = %.3f v",E_cell)
diff --git a/3876/CH10/EX10.7/Ex10_7.sce b/3876/CH10/EX10.7/Ex10_7.sce
index d78aa1eae..145c9977b 100644
--- a/3876/CH10/EX10.7/Ex10_7.sce
+++ b/3876/CH10/EX10.7/Ex10_7.sce
@@ -1,20 +1,22 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
+R= 8.31 //electrical unit J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
 c= 0.02 //molar
 c1= 0.1 //molar
 c2= 1 //molar
 c3= 1 //molar
-E1= 1.486 //v
+E_cell_0= 1.486 //voltage
 
 //CALCULATIONS
-E= E1-R*(273+T)*2.3*log10(c*c1**2/(c2*c3))/(2*F)
+E_cell= E_cell_0-R*(273+T)*2.3*log10(c*c1**2/(c2*c3))/(2*F)
 
 //RESULTS
-mprintf("Potential of the cell = %.3f v",E)
+mprintf("Potential of the cell = %.3f v",E_cell)
diff --git a/3876/CH10/EX10.8/Ex10_8.sce b/3876/CH10/EX10.8/Ex10_8.sce
index 597eadb0c..e5628727c 100644
--- a/3876/CH10/EX10.8/Ex10_8.sce
+++ b/3876/CH10/EX10.8/Ex10_8.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 10 Electmotive Force
 
 clc;
 clear;
 
 //Initialisation of Variables
-R= 8.31 //J/mol K
-T= 25 //C
-F= 96500 //coloums
+R= 8.31 //electrical unit J/mol K
+T= 25 //temperature in Celsius
+F= 96500 //charge in coloums
 c= 0.08 //molar
 c1= 0.04 //molar
 
@@ -15,5 +17,5 @@ E= R*(T+273)*log(c/c1)/(2*F)
 E1= 2*E
 
 //RESULTS
-mprintf("Potential of the cell = %.3f v",E)
-mprintf("\nPotential of the cell = %.3f v",E1)
+mprintf("Potential of the cell = %.4f v",E)
+mprintf("\nPotential of the cell = %.4f v",E1)
diff --git a/3876/CH11/EX11.1/Ex11_1.sce b/3876/CH11/EX11.1/Ex11_1.sce
index afe3e664b..ca6989f8e 100644
--- a/3876/CH11/EX11.1/Ex11_1.sce
+++ b/3876/CH11/EX11.1/Ex11_1.sce
@@ -1,16 +1,18 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 11 Thermodynamics Some Basic Concepts
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
-T1= 75 //C
-k= 6.45 //cal per mole per degree
-k1= 1.41*10**-3 //cal per mole per degree k^-1
-k2= -8.1*10**-8 //cal per mole per degree k^-2
-m= 14 //gms
-M= 28 //gms
+T= 25 //temperature in Celsius
+T1= 75 //temperature in Celsius
+k= 6.45 //cal per mole per degree - molar heat capacity
+k1= 1.41*10**-3 //cal per mole per degree k^-1  - molar heat capacity
+k2= -8.1*10**-8 //cal per mole per degree k^-2  - molar heat capacity
+m= 14 //weight in gms
+M= 28 //weight in gms
 
 //CALCULATIONS
 Cp= k+k1*(273+T)+k2*(273+T)**2
@@ -22,3 +24,5 @@ H1= (m/M)*(k*(T1-T)+(k1/2)*((273+T1)**2-(273+T)**2)+(k2/3)*((273+T1)**3-(273+T)*
 //RESULTS
 mprintf("Heat required= %.1f cal",H)
 mprintf("\nValue of dH= %.1f cal",H1)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH11/EX11.2/Ex11_2.sce b/3876/CH11/EX11.2/Ex11_2.sce
index 49e6a0e70..6ad513b03 100644
--- a/3876/CH11/EX11.2/Ex11_2.sce
+++ b/3876/CH11/EX11.2/Ex11_2.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 11 Thermodynamics Some Basic Concepts
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 64 //gms
-M= 32 //gms
-T= 100 //C
-T1= 0 //C
-cp= 7.05 //cal per mole per degree
-cp1= 5.06 //cal per mole per degree
+m= 64 //weight in gms
+M= 32 //weight in gms
+T= 100 //temperature in Celsius
+T1= 0 //temperature in Celsius
+cp= 7.05 //cal per mole per degree - avg heat capacity
+cp1= 5.06 //cal per mole per degree - avg heat capacity
 
 //CALCULATIONS
 H= cp*(m/M)*(T-T1)
diff --git a/3876/CH11/EX11.3/Ex11_3.sce b/3876/CH11/EX11.3/Ex11_3.sce
index 2b03af345..01b796851 100644
--- a/3876/CH11/EX11.3/Ex11_3.sce
+++ b/3876/CH11/EX11.3/Ex11_3.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 11 Thermodynamics Some Basic Concepts
 
 clc;
@@ -5,10 +7,10 @@ clear;
 
 //Initialisation of Variables
 n= 2 //moles
-R= 1.99 //cal er mole per degree
-T= 80 //C
-H1= 94.3 //cal per gram
-M= 78 //gms per mole
+R= 1.99 //cal per mole per degree
+T= 80 //temperature in Celsius
+H1= 94.3 //cal per gram - heat of vaporization
+M= 78 //weight of benzene in gms per mole
 
 //CALCULATIONS
 w= n*R*(273+T)
diff --git a/3876/CH11/EX11.4/Ex11_4.sce b/3876/CH11/EX11.4/Ex11_4.sce
index 20d75e37f..f800fa9a5 100644
--- a/3876/CH11/EX11.4/Ex11_4.sce
+++ b/3876/CH11/EX11.4/Ex11_4.sce
@@ -1,28 +1,30 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 11 Thermodynamics Some Basic Concepts
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 9 //gms
-T= -10 //C
-T1= 0 //C
-R= 0.5 //cal per gram per degree
-H= 79.7 //cal per gram
-R1= 1 //cal per gram per degree
-T2= 100 //C
-H1= 539.7 //cal per gm
-R2= 8.11 //cal per gram per degree
-M= 18 //gms
-T3= 40 //C
+m= 9 //weight in gms
+T= -10 //temperature in Celsius
+T1= 0 //temperature in Celsius
+R= 0.5 //cal per gram per degree - heat capacity
+H= 79.7 //cal per gram - heat of vaporization
+R1= 1 //cal per gram per degree - heat of evaporation
+T2= 100 ///temperature in Celsius
+H1= 539.7 //cal per gm - heat of vaporization
+R2= 8.11 //cal per gram per degree - heat of evaporation
+M= 18 //weight in gms
+T3= 40 //temperature in Celsius
 
 //CALCULATIONS
-dH= m*R*(T1-T)
-dH1= m*H
-dH2= m*R1*(T2-T1)
-dH3= m*H1
-dH4= (m/M)*R2*(T3-T1)
-dH5= dH+dH1+dH2+dH3+dH4
+dH1= m*R*(T1-T)
+dH2= m*H
+dH3= m*R1*(T2-T1)
+dH4= m*H1
+dH5= (m/M)*R2*(T3-T1)
+dH= dH1+dH2+dH3+dH4+dH5
 
 //RESULTS
-mprintf("Value of dH= %.1f cal",dH5)
+mprintf("Value of dH= %.1f cal",dH)
diff --git a/3876/CH12/EX12.1/Ex12_1.sce b/3876/CH12/EX12.1/Ex12_1.sce
index cf4c48aff..36c58bc12 100644
--- a/3876/CH12/EX12.1/Ex12_1.sce
+++ b/3876/CH12/EX12.1/Ex12_1.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
 clc;
 clear;
 
 //Initialisation of Variables
-H= -771400 //cal
-n= 7 //moles
-n1= 7.5 //moles
-T= 25 //C
+H= -771400 //heat of combustion in cal
+n= 7 //moles of CO2
+n1= 7.5 //moles of O2
+T= 25 //temperature in Celsius
 R= 2 //cal mole per degree
 
 //CALCULATIONS
diff --git a/3876/CH12/EX12.2/Ex12_2.sce b/3876/CH12/EX12.2/Ex12_2.sce
index 5c8d18663..e18726acd 100644
--- a/3876/CH12/EX12.2/Ex12_2.sce
+++ b/3876/CH12/EX12.2/Ex12_2.sce
@@ -1,15 +1,19 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
 clc;
 clear;
 
 //Initialisation of Variables
-H= -94.052 //kcal
-H1= -68.317 //kcal
-H2= -780.98 //kcal
+H= -94.052 //kcal  heat of combustion
+H1= -68.317 //kcal  heat of combustion
+H2= -780.98 //kcal  heat of combustion
 
 //CALCULATIONS
 H3= 6*H+3*H1-H2
 
 //RESULTS
 mprintf("Heat of formation = %.3f kcal",H3)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH12/EX12.3/Ex12_3.sce b/3876/CH12/EX12.3/Ex12_3.sce
index 3f61c3fc5..8ebee0fa8 100644
--- a/3876/CH12/EX12.3/Ex12_3.sce
+++ b/3876/CH12/EX12.3/Ex12_3.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
 clc;
 clear;
 
 //Initialisation of Variables
-H= -94.052 //kcal
-H1= -68.32 //kcal
-H2= 11.718 //kcal
+H= -94.052 //kcal   heat of combustion
+H1= -68.32 //kcal   heat of combustion
+H2= 11.718 //kcal  heat of combustion
 
 //CALCULATIONS
 H3= 6*H+3*H1-H2
diff --git a/3876/CH12/EX12.4/Ex12_4.sce b/3876/CH12/EX12.4/Ex12_4.sce
index 52c396294..ec1920526 100644
--- a/3876/CH12/EX12.4/Ex12_4.sce
+++ b/3876/CH12/EX12.4/Ex12_4.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
@@ -5,9 +7,9 @@ clc;
 clear;
 
 //Initialisation of Variables
-H= -66.36 //kcal
-H1= 12.5 //k cal
-H2= -68.317 //kcal
+H= -66.36 //kcal   heat of combustion
+H1= 12.5 //k cal   heat of combustion
+H2= -68.317 //kcal  heat of combustion
 
 //CALCULATIONS
 H3= H-H1-H2
diff --git a/3876/CH12/EX12.5/Ex12_5.sce b/3876/CH12/EX12.5/Ex12_5.sce
index 3013af0dc..f120bc572 100644
--- a/3876/CH12/EX12.5/Ex12_5.sce
+++ b/3876/CH12/EX12.5/Ex12_5.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
@@ -5,12 +7,12 @@ clc;
 clear;
 
 //Initialisation of Variables
-T= 90 //C
-T1= 25 //C
+T= 90//temperature in Celsius
+T1= 25//temperature in Celsius
 Cp= 6.9 //cal per mole per degree
-CP1= 7.05 //cal per mole per degree
-Cp2= 18 //cal per mole per degree
-H= -68370 //kcal
+CP1= 7.05 //cal per mole per degree - heat capacity
+Cp2= 18 //cal per mole per degree - heat capacity
+H= -68370 //kcal - heat of formation
 
 //CALCULATIONS
 H1= H+(Cp2-Cp-0.5*CP1)*(T-T1)
diff --git a/3876/CH12/EX12.6/Ex12_6.sce b/3876/CH12/EX12.6/Ex12_6.sce
index be91caff2..d5af5e9f4 100644
--- a/3876/CH12/EX12.6/Ex12_6.sce
+++ b/3876/CH12/EX12.6/Ex12_6.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 12 Thermodynamics Thermodynamic chemistry
 
@@ -5,15 +7,15 @@ clc;
 clear;
 
 //Initialisation of Variables
-Cp= 2.7 //cal per mole per degree
-CP1= 6.9 //cal per mole per degree
-Cp2= 15.4 //cal per mole per degree
-H= -20.24 //kcal
-T= 200 //C
-T1= 25 //C
+Cp= 2.7 //cal per mole per degree  - heat capacity
+CP1= 6.9 //cal per mole per degree  - heat capacity
+Cp2= 15.4 //cal per mole per degree - heat capacity
+dH_25= -20.24 //kcal  - heat of formation
+T= 200 //temperature in Celsius
+T1= 25 //temperature in Celsius
 
 //CALCULATIONS
-H1= H+(Cp2-2*Cp-3*CP1)*((T-T1)/1000)
+dH_200= dH_25+(Cp2-2*Cp-3*CP1)*((T-T1)/1000)
 
 //RESULTS
-mprintf("Heat of formation= %.2f kcal",H1)
+mprintf("Heat of formation= %.2f kcal",dH_200)
diff --git a/3876/CH13/EX13.1/Ex13_1.sce b/3876/CH13/EX13.1/Ex13_1.sce
index a59b66cd5..aaf3d7fb1 100644
--- a/3876/CH13/EX13.1/Ex13_1.sce
+++ b/3876/CH13/EX13.1/Ex13_1.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-H= 540 //cal per gram
-m= 9 //gms
-T= 100 //C
+H= 540 //cal per gram - heat of vaporization
+m= 9 //weight in gms
+T= 100 //temperature in Celsius
 
 //CALCULATIONS
 S= H*m/(273+T)
diff --git a/3876/CH13/EX13.10/Ex13_10.sce b/3876/CH13/EX13.10/Ex13_10.sce
index dd9d94978..5e64b1244 100644
--- a/3876/CH13/EX13.10/Ex13_10.sce
+++ b/3876/CH13/EX13.10/Ex13_10.sce
@@ -1,18 +1,22 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-F= 18430 //cal
-F1= -31350 //cal
-F2= 26224 //cal
+dF_Ag_plus= 18430 //cal - free energy of formation
+dF_Cl_minus= -31350 //cal - free energy of formation
+dF_AgCl= 26224 //cal - free energy of formation
 R= 1.99 //cal/mole K
-T= 25 //C
+T= 25 //temperature in Celsius
 
 //CALCULATIONS
-F3= F+F1+F2
-Ksp= 10**(-F3/(R*(273+T)*2.303))
+dF= dF_Ag_plus+dF_Cl_minus+dF_AgCl
+Ksp= 10**(-dF/(R*(273+T)*2.303))
 
 //RESULTS
 mprintf("Solubility product = %.2e",Ksp)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH13/EX13.11/Ex13_11.sce b/3876/CH13/EX13.11/Ex13_11.sce
index 0eda0871f..814e2d98b 100644
--- a/3876/CH13/EX13.11/Ex13_11.sce
+++ b/3876/CH13/EX13.11/Ex13_11.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-F= -51108 //cal
-f= 96500 //coloumbs
+F= -51108 //cal - free energy of formation
+f= 96500 //charge in coloumbs
 n= 2 //moles
 
 //CALCULATIONS
 E= -F*4.184/(n*f)
 
 //RESULTS
-mprintf("Value of E = %.2f v",E)
+mprintf("Value of E = %.3f v",E)
diff --git a/3876/CH13/EX13.12/Ex13_12.sce b/3876/CH13/EX13.12/Ex13_12.sce
index 845984353..46b2bbe24 100644
--- a/3876/CH13/EX13.12/Ex13_12.sce
+++ b/3876/CH13/EX13.12/Ex13_12.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-F1= 31350 //cal
-F2= 26224 //cal
-F= 96500 //coloumbs
+F1= 31350 //cal - free energy of formation
+F2= 26224 //cal - free energy of formation
+F= 96500 //charge in coloumbs
 
 //CALCULATIONS
 F3= -F1+F2
diff --git a/3876/CH13/EX13.13/Ex13_13.sce b/3876/CH13/EX13.13/Ex13_13.sce
index 0c9d600f3..3df2bd183 100644
--- a/3876/CH13/EX13.13/Ex13_13.sce
+++ b/3876/CH13/EX13.13/Ex13_13.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
+T= 25 //temperature in Celsius
 a= 0.2 //molar
-P= 1 //atm
-F1= -5126 //cal
+P= 1 //pressure in atm
+F1= -5126 //cal  - free energy of formation
 R= 2 //cal/mole K
 
 //CALCULATIONS
diff --git a/3876/CH13/EX13.14/Ex13_14.sce b/3876/CH13/EX13.14/Ex13_14.sce
index 1256c353d..1b4bb16a7 100644
--- a/3876/CH13/EX13.14/Ex13_14.sce
+++ b/3876/CH13/EX13.14/Ex13_14.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
+T= 25 //temperature in Celsius
 F= 1160 //cal
-P= 0.1 //atm
-P1= 1 //atm
+P= 0.1 //pressure in atm
+P1= 1 //pressure in atm
 R= 2 //cal/mole K
 
 //CALCULATIONS
@@ -17,3 +19,5 @@ F2= F+R*(273+T)*log(P1/P**2)
 //RESULTS
 mprintf("Value of F = %.0f cal",F1)
 mprintf("\nValue of F = %.0f cal",F2)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH13/EX13.15/Ex13_15.sce b/3876/CH13/EX13.15/Ex13_15.sce
index 3483c47fb..c535542f7 100644
--- a/3876/CH13/EX13.15/Ex13_15.sce
+++ b/3876/CH13/EX13.15/Ex13_15.sce
@@ -1,20 +1,25 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
-H= -94.05 //kcal
-H1= -26.42 //kcal
-S= 51.06 //cal per degree
-S1= -47.3 //cal per degree
-S2= -24.5 //cal per degree
+T= 25 //temperature in Celsius
+H_CO2= -94.05 //kcal - enthalpy
+H_CO= -26.40 //kcal - enthalpy
+S1= 51.06 //cal per degree
+S2= -47.3 //cal per degree
+S3= -24.5 //cal per degree
 
 //CALCULATIONS
-dH= (H-H1)*1000
-dS= S+S1+S2
-F= dH-(273+T)*dS
+dH= (H_CO2-H_CO)*1000
+dS= S1+S2+S3
+dF= dH-(273+T)*dS
 
 //RESULTS
-mprintf("Value of F = %.0f cal",F)
+mprintf("Value of F = %.0f cal",dF)
+
+//The difference in the solution compared to textbook is due to round off error:
+//dS is being taken as -20.7 in the textbook whereas it is being calculated as -20.74 in the code
diff --git a/3876/CH13/EX13.2/Ex13_2.sce b/3876/CH13/EX13.2/Ex13_2.sce
index df83696c8..1bd313bae 100644
--- a/3876/CH13/EX13.2/Ex13_2.sce
+++ b/3876/CH13/EX13.2/Ex13_2.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 9 //gms
-H= 79.7 //cal per gram
-T= 0 //C
+m= 9 //weight in gms
+H= 79.7 //cal per gram - heat of fusion
+T= 0 //temperature in Celsius
 
 //CALCULATIONS
 S= m*H/(273+T)
diff --git a/3876/CH13/EX13.3/Ex13_3.sce b/3876/CH13/EX13.3/Ex13_3.sce
index 99a48673b..e85b9b4fd 100644
--- a/3876/CH13/EX13.3/Ex13_3.sce
+++ b/3876/CH13/EX13.3/Ex13_3.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
@@ -5,11 +7,11 @@ clc;
 clear;
 
 //Initialisation of Variables
-m= 14 //gms
-M= 28 //gms
+m= 14 //weight in gms
+M= 28 //weight in gms
 R= 1.99 // cal per mole per degree
-V= 30 //lit
-v1= 10 //lit
+V= 30 //volume in lit
+v1= 10 //volume in lit
 
 //CALCULATIONS
 S1= (m/M)*R*2.303*log10(V/v1)
diff --git a/3876/CH13/EX13.4/Ex13_4.sce b/3876/CH13/EX13.4/Ex13_4.sce
index c1fca5842..81e3cf2c7 100644
--- a/3876/CH13/EX13.4/Ex13_4.sce
+++ b/3876/CH13/EX13.4/Ex13_4.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 14 //gms
-M= 28 //gms
-S= 6.94 //cal per mole
-T= 127 //C
-T1= 27 //C
-S1= 4.94 //cal per mole
+m= 14 //weight in gms
+M= 28 //weight in gms
+S= 6.94 //cal per mole - heat capacity
+T= 127 //temperature in Celsius
+T1= 27 //temperature in Celsius
+S1= 4.94 //cal per mole - heat capacity
 
 //CALCULATIONS
 dS= (m/M)*S*log((273+T)/(273+T1))
diff --git a/3876/CH13/EX13.5/Ex13_5.sce b/3876/CH13/EX13.5/Ex13_5.sce
index fad363737..23916e5b0 100644
--- a/3876/CH13/EX13.5/Ex13_5.sce
+++ b/3876/CH13/EX13.5/Ex13_5.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-Scl= 53.29 //E.U
-Sag= 10.21 //E.U
-Sagcl= 22.97 //E.U
+Scl= 53.29 //standard entropy of formation E.U
+Sag= 10.21 //standard entropy of formation E.U
+Sagcl= 22.97 //standard entropy of formation E.U
 
 //CALCULATIONS
 dS= Sagcl-Sag-0.5*Scl
diff --git a/3876/CH13/EX13.6/Ex13_6.sce b/3876/CH13/EX13.6/Ex13_6.sce
index fb253cb5d..ba4f491ec 100644
--- a/3876/CH13/EX13.6/Ex13_6.sce
+++ b/3876/CH13/EX13.6/Ex13_6.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-Scl= 13.17 //E.U
-Sag= 17.67 //E.U
-Sagcl= 22.97 //E.U
+Scl= 13.17 //standard entropy of formation E.U
+Sag= 17.67 //standard entropy of formation E.U
+Sagcl= 22.97 //standard entropy of formation E.U
 
 //CALCULATIONS
 dS= Scl+Sag-Sagcl
diff --git a/3876/CH13/EX13.7/Ex13_7.sce b/3876/CH13/EX13.7/Ex13_7.sce
index f3467d78b..daa39321c 100644
--- a/3876/CH13/EX13.7/Ex13_7.sce
+++ b/3876/CH13/EX13.7/Ex13_7.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-F1= -94260 //cal
-F2= -56690 //cal
-F3= -7860 //cal
+F1= -94260 //cal free energy of formation
+F2= -56690 //cal free energy of formation
+F3= -7860 //cal free energy of formation
 
 //CALCULATIONS
 F= 2*F1+3*F2-F3
diff --git a/3876/CH13/EX13.8/Ex13_8.sce b/3876/CH13/EX13.8/Ex13_8.sce
index 5b67de43e..03ef557b0 100644
--- a/3876/CH13/EX13.8/Ex13_8.sce
+++ b/3876/CH13/EX13.8/Ex13_8.sce
@@ -1,14 +1,19 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
-F1= -35180 //cal
+T= 25 //temperature in Celsius
+F_Zn2= -35180 //standard free energy cal of Zn2
+F_H2=0 //standard free energy cal of H2
+F_Zn=0 //standard free energy cal of Zn
+F_H=0 //standard free energy cal of H
 
 //CALCULATIONS
-F= F1
+F= F_Zn2 + F_H2 - F_Zn - (2 * F_H)
 
 //RESULTS
-mprintf("Value of dF = %.2f",F)
+mprintf("Value of dF = %.2f cal",F)
diff --git a/3876/CH13/EX13.9/Ex13_9.sce b/3876/CH13/EX13.9/Ex13_9.sce
index 1e78d944e..b888979ff 100644
--- a/3876/CH13/EX13.9/Ex13_9.sce
+++ b/3876/CH13/EX13.9/Ex13_9.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 13 Thermodynamics Entropy and Free Energy
 
 clc;
 clear;
 
 //Initialisation of Variables
-F= -51180 //cal
-T= 25 //C
+F= -51180 //cal ,free energy
+T= 25 //temperature in Celsius
 R= 1.99 //cal/mole K
 
 //CALCULATIONS
 K= 10**(-F/(R*(273+T)*2.303))
 
 //RESULTS
-mprintf("Equilibrium constant = %.2e",K)
+mprintf("Equilibrium constant = %.0e",K)
diff --git a/3876/CH14/EX14.1/Ex14_1.sce b/3876/CH14/EX14.1/Ex14_1.sce
index 43be88d31..1a084c5aa 100644
--- a/3876/CH14/EX14.1/Ex14_1.sce
+++ b/3876/CH14/EX14.1/Ex14_1.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 14 Determination of Hydroniumion Concentrations
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= 0.232 //v
-R= 0.0592
-p= 1 //atm
-R1= 0.0296
-P= 740 //atm
+E= 0.232 //potential in voltage
+R= 0.0592  //constant
+p= 1 //pressure in atm
+R1= 0.0296// constant
+P= 740 //pressure in atm
 
 //CALCULATIONS
 pH= E/R
diff --git a/3876/CH14/EX14.2/Ex14_2.sce b/3876/CH14/EX14.2/Ex14_2.sce
index a17e2453e..fe03bfdf1 100644
--- a/3876/CH14/EX14.2/Ex14_2.sce
+++ b/3876/CH14/EX14.2/Ex14_2.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 14 Determination of Hydroniumion Concentrations
 
 clc;
 clear;
 
 //Initialisation of Variables
-e= 0.266 //v
-R= 0.0592
+e= 0.266 //potential in voltage
+R= 0.0592  //constant
 
 //CALCULATIONS
 pH= e/R
diff --git a/3876/CH14/EX14.3/Ex14_3.sce b/3876/CH14/EX14.3/Ex14_3.sce
index 37eeefda7..d3211506d 100644
--- a/3876/CH14/EX14.3/Ex14_3.sce
+++ b/3876/CH14/EX14.3/Ex14_3.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 14 Determination of Hydroniumion Concentrations
 
 clc;
 clear;
 
 //Initialisation of Variables
-e= 0.323 //v
-R= 0.0592
+e= 0.323 //potential in voltage
+R= 0.0592  //constant
 c= 0.001 //molar
 
 //CALCULATIONS
diff --git a/3876/CH14/EX14.4/Ex14_4.sce b/3876/CH14/EX14.4/Ex14_4.sce
index e327efecd..b8904d556 100644
--- a/3876/CH14/EX14.4/Ex14_4.sce
+++ b/3876/CH14/EX14.4/Ex14_4.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 14 Determination of Hydroniumion Concentrations
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= 0.527 //v
-T= 25 //C
-R= 0.0592
-e= -0.246 //v
+E= 0.527 //potential in v
+T= 25 //temperature in Celsius
+R= 0.0592  //constant
+e= -0.246 //potential in v
 
 //CALCULATIONS
 pH= -(-E-e)/R
diff --git a/3876/CH14/EX14.5/Ex14_5.sce b/3876/CH14/EX14.5/Ex14_5.sce
index 48e08de47..381a7283c 100644
--- a/3876/CH14/EX14.5/Ex14_5.sce
+++ b/3876/CH14/EX14.5/Ex14_5.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 14 Determination of Hydroniumion Concentrations
 
 clc;
 clear;
 
 //Initialisation of Variables
-E= 0.034 //v
-E1= -0.280 //v
-E2= -0.699 //v
-E3= 0.0592
+E= 0.034 //potential in v
+E1= -0.280 //potential in v
+E2= -0.699 //potential in v
+E3= 0.0592 //constant
 
 //CALCULATIONS
 pH= (E1-E-E2)/E3
diff --git a/3876/CH16/EX16.1/Ex16_1.sce b/3876/CH16/EX16.1/Ex16_1.sce
index 7672f8477..3e6c6f6b7 100644
--- a/3876/CH16/EX16.1/Ex16_1.sce
+++ b/3876/CH16/EX16.1/Ex16_1.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 16 Oxidation Reduction Potentials
 
 clc;
diff --git a/3876/CH16/EX16.2/Ex16_2.sce b/3876/CH16/EX16.2/Ex16_2.sce
index c26668a11..d15a3cc71 100644
--- a/3876/CH16/EX16.2/Ex16_2.sce
+++ b/3876/CH16/EX16.2/Ex16_2.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 16 Oxidation Reduction Potentials
 
 clc;
diff --git a/3876/CH16/EX16.3/Ex16_3.sce b/3876/CH16/EX16.3/Ex16_3.sce
index 3198503b3..171175a3f 100644
--- a/3876/CH16/EX16.3/Ex16_3.sce
+++ b/3876/CH16/EX16.3/Ex16_3.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 16 Oxidation Reduction Potentials
 
 clc;
diff --git a/3876/CH17/EX17.1/Ex17_1.sce b/3876/CH17/EX17.1/Ex17_1.sce
index 2af9bef71..5115b6d14 100644
--- a/3876/CH17/EX17.1/Ex17_1.sce
+++ b/3876/CH17/EX17.1/Ex17_1.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 17 Speed of Reaction Catalysis
 
 clc;
diff --git a/3876/CH17/EX17.2/Ex17_2.sce b/3876/CH17/EX17.2/Ex17_2.sce
index 7a18e6893..c865f1ed0 100644
--- a/3876/CH17/EX17.2/Ex17_2.sce
+++ b/3876/CH17/EX17.2/Ex17_2.sce
@@ -1,17 +1,20 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 17 Speed of Reaction Catalysis
+// Example 17.3 in textbook
 
 clc;
 clear;
 
 //Initialisation of Variables
-t= 10 //min
-c= 0.01 //molar
-c1= 0.00464 //molar
+t= 10 //time in min
+a0= 0.01 //concentration in molar
+a= 0.00464 //concentration of base found in molar
 
 //CALCULATIONS
-k= (c-c1)/(c*c1*t)
-T= 1/(k*0.01)
+k= (a0-a)/(a0*a*t)
+t_half= 1/(k*0.01)
 
 //RESULTS
-mprintf("Velocity constant= %.1f min^-1",k)
-mprintf("\nHalf-time period= %.1f min",T)
+mprintf("Velocity constant= %.2f min^-1",k)
+mprintf("\nHalf-time period= %.1f min",t_half)
diff --git a/3876/CH2/EX2.1/Ex2_1.sce b/3876/CH2/EX2.1/Ex2_1.sce
index 8f04df680..c6a2075d5 100644
--- a/3876/CH2/EX2.1/Ex2_1.sce
+++ b/3876/CH2/EX2.1/Ex2_1.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-P= 730 //mm
-V= 20 //litres
-T= -20 //C
-P1= 760 //mm
-T1= 0 //C
+P= 730 //pressure in mm
+V= 20 //volume in litres
+T= -20 //temperature in Celsius
+P1= 760 //pressure in mm
+T1= 0 //temperature in Celsius
 
 //CALCULATIONS
 V1= P*V*(273+T1)/((273+T)*760)
diff --git a/3876/CH2/EX2.10/Ex2_10.sce b/3876/CH2/EX2.10/Ex2_10.sce
index d3dcc972f..b0f86603a 100644
--- a/3876/CH2/EX2.10/Ex2_10.sce
+++ b/3876/CH2/EX2.10/Ex2_10.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 2 Gases
 
@@ -5,12 +7,12 @@ clc;
 clear;
 
 //Initialisation of Variables
-V= 0.5 //lit
-T= 50 //C
-n= 1 //mole
-R= 0.0821 //lit atm mole^-1
-a= 4.28*10**-2 //litres mole^-1
-b= 3.6 //arm mole^-2 lit^2
+V= 0.5 //volume in litres
+T= 50 //temperature in Celsius
+n= 1 //no of moles
+R= 0.0821 //gas constant in lit atm mole^-1
+a= 4.28*10**-2 //Van der Waals equation a in litres mole^-1
+b= 3.6 //Van der Waals equation b in arm mole^-2 lit^2
 
 //CALCULATIONS
 P= n*R*(273+T)/V
diff --git a/3876/CH2/EX2.2/Ex2_2.sce b/3876/CH2/EX2.2/Ex2_2.sce
index 20e95f7f2..20e68fab9 100644
--- a/3876/CH2/EX2.2/Ex2_2.sce
+++ b/3876/CH2/EX2.2/Ex2_2.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-N= 6*10**23 //molcules
-R= 0.0821 //lit atm mole^-1
-V= 20 //lit
-P= 730 //mm of Hg
-T= -20 //C
+N= 6.02*10**23 //Avogadro constant for molecules
+R= 0.0821 //gas constant in lit atm mole^-1
+V= 20 //volume in lit
+P= 730 //pressure in mm of Hg
+T= -20 //temperature in Celsius
 
 //CALCULATIONS
 M= N*P*V/(760*R*(273+T))
diff --git a/3876/CH2/EX2.3/Ex2_3.sce b/3876/CH2/EX2.3/Ex2_3.sce
index f5937d4ea..5d7bcfb2e 100644
--- a/3876/CH2/EX2.3/Ex2_3.sce
+++ b/3876/CH2/EX2.3/Ex2_3.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-P= 100 //cm
-m= 2*10**20 //molecules
-N= 6*10**23
-R= 0.0821 //lit atm mole^-1
-T= 27 //C
+P= 100 //pressure in cm
+m= 2*10**20 //molecules of nitrogen
+N= 6*10**23 //Avogadro constant for molecules
+R= 0.0821 //gas constant in lit atm mole^-1
+T= 27 //temperature in Celsius
 
 //CALCULATIONS
 V= m*R*(T+273)*760*100/(N*P)
diff --git a/3876/CH2/EX2.4/Ex2_4.sce b/3876/CH2/EX2.4/Ex2_4.sce
index 9032f3e43..7367d8040 100644
--- a/3876/CH2/EX2.4/Ex2_4.sce
+++ b/3876/CH2/EX2.4/Ex2_4.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-P= 752 //mm
-V= 0.2 //lit
-T= 21 //C
-R= 0.0821 //lit atm mole^-1
-m= 0.980 //gms
+P= 752 //pressure in mm
+V= 0.2 //volume in litres
+T= 21 //temperature in Celsius
+R= 0.0821 //gas constant in lit atm mole^-1
+m= 0.980 //chloroform in gms
 
 //CALCULATIONS
 M= m*R*(T+273)*760/(V*P)
diff --git a/3876/CH2/EX2.5/Ex2_5.sce b/3876/CH2/EX2.5/Ex2_5.sce
index bdb622f8a..c9e29cbfb 100644
--- a/3876/CH2/EX2.5/Ex2_5.sce
+++ b/3876/CH2/EX2.5/Ex2_5.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 2 Gases
 
@@ -37,4 +39,7 @@ mprintf("\nPO2=%.3f atm",pO2)
 mprintf("\nPH2=%.3f atm",pH2)
 mprintf("\n The total pressure is: %.3f atm",Tp)
 mprintf("\n The total number of moles is: %.2f moles",Tm)
-mprintf("\nTotal pressure multiplied by mole fraction: %.3f",Tpc)
+mprintf("\nTotal pressure multiplied by mole fraction: %.3f atm",Tpc)
+
+//The difference in the solution compared to textbook is due to round off error:
+//PH2 is being taken as 0.498 in the textbook whereas it is being calculated as 0.497 in the code
diff --git a/3876/CH2/EX2.6/Ex2_6.sce b/3876/CH2/EX2.6/Ex2_6.sce
index dbb429129..26cd90e57 100644
--- a/3876/CH2/EX2.6/Ex2_6.sce
+++ b/3876/CH2/EX2.6/Ex2_6.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-P= 23.8 //mm
-V= 0.5 //lit
-R= 0.0821 //lit atm mole^-1
-T= 25 //C
+P= 23.8 //pressure in mm
+V= 0.5 //volume in litres
+R= 0.0821 //gas constant in lit atm mole^-1
+T= 25 //temperature in Celsius
 
 //CALCULATIONS
 P1= 760-P
diff --git a/3876/CH2/EX2.7/Ex2_7.sce b/3876/CH2/EX2.7/Ex2_7.sce
index 0869d0c99..fb9355a81 100644
--- a/3876/CH2/EX2.7/Ex2_7.sce
+++ b/3876/CH2/EX2.7/Ex2_7.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-t= 20 //min
-t1= 19.4 //min
-M= 32 //gms
+t= 20 //time for diffusion in min
+t1= 19.4 //time for diffusion in min
+M= 32 //weight in gms
 
 //CALCULATIONS
 x= M*t1**2/t**2
diff --git a/3876/CH2/EX2.8/Ex2_8.sce b/3876/CH2/EX2.8/Ex2_8.sce
index c3f4eddd1..658a26a4c 100644
--- a/3876/CH2/EX2.8/Ex2_8.sce
+++ b/3876/CH2/EX2.8/Ex2_8.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-R= 8.31*10**7 //ergs mole^-1
-T= 27 //C
-M= 28 //gram per mole
+R= 8.31*10**7 //universal gas constant in ergs mole^-1
+T= 27 //temperature in Celsius
+M= 28 //weight in gram per mole
 
 //CALCULATIONS
 c= sqrt(3*R*(273+T)/M)
diff --git a/3876/CH2/EX2.9/Ex2_9.sce b/3876/CH2/EX2.9/Ex2_9.sce
index 0f432cac7..927bc6bac 100644
--- a/3876/CH2/EX2.9/Ex2_9.sce
+++ b/3876/CH2/EX2.9/Ex2_9.sce
@@ -1,15 +1,18 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 2 Gases
 
 clc;
 clear;
 
 //Initialisation of Variables
-V= 5.16*10**14 //cm per sec
-M2= 28 //gms
-M1= 2.02 //gms
+V= 5.16*10**4 //velocity in cm per sec
+M2= 28 //weight in gms
+M1= 2.02 //weight in gms
 
 //CALCULATIONS
-c1= V*sqrt(M2/M1)
+c1= sqrt(M2/M1) * V
+c1=c1/10000   //cm per sec
 
 //RESULTS
-mprintf("Velocity of hydrogen molecule = %.2e cm per sec",c1)
+mprintf("Velocity of hydrogen molecule = %.1f*10^4 cm per sec",c1)
diff --git a/3876/CH20/EX20.1/Ex20_1.sce b/3876/CH20/EX20.1/Ex20_1.sce
index 60b6a72e8..78a2e7854 100644
--- a/3876/CH20/EX20.1/Ex20_1.sce
+++ b/3876/CH20/EX20.1/Ex20_1.sce
@@ -1,20 +1,24 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 20 Radiochemistry
 
 clc;
 clear;
 
 //Initialisation of Variables
-t= 4.5*10**9 //years
-t1= 1590 //years
+U1_thalf= 4.5*10**9 //half-life period of Uranium 1 in years
+Ra_thalf= 1590 //half-life period of Radium in years
 
 //CALCULATIONS
-l= log10(2)/(t*0.4343)
-l1= log10(2)/(t1*0.4343)
-r= l1/l
-r1= t/t1
+lambda_U1= log10(2)/(U1_thalf*0.4343)
+lambda_Ra= log10(2)/(Ra_thalf*0.4343)
+//solution from disintegration constants
+r= lambda_Ra/lambda_U1
+//solution from half-life periods
+r1= U1_thalf/Ra_thalf
 
 //RESULTS
-mprintf("Disintegration constant= %.2e yr^-1",l)
-mprintf("\nDisintegration constant= %.2e yr^-1",l1)
-mprintf("\nRelative proportion= %.2e",r)
-mprintf("\nRelative proportion= %.2e",r1)
+mprintf("Disintegration constant for Uranium 1= %.2e yr^-1",lambda_U1)
+mprintf("\nDisintegration constant for Radium= %.2e yr^-1",lambda_Ra)
+mprintf("\nRelative proportion(from disintegration constants)= %.2e",r)
+mprintf("\nRelative proportion(from half-life periods)= %.2e",r1)
diff --git a/3876/CH3/EX3.1/Ex3_1.sce b/3876/CH3/EX3.1/Ex3_1.sce
index 0605b9394..6aeebdc7e 100644
--- a/3876/CH3/EX3.1/Ex3_1.sce
+++ b/3876/CH3/EX3.1/Ex3_1.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 3 Liquids
 
diff --git a/3876/CH3/EX3.2/Ex3_2.sce b/3876/CH3/EX3.2/Ex3_2.sce
index f1c13142c..280f33131 100644
--- a/3876/CH3/EX3.2/Ex3_2.sce
+++ b/3876/CH3/EX3.2/Ex3_2.sce
@@ -1,16 +1,18 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 3 Liquids
 
 clc;
 clear;
 
 //Initialisation of Variables
-d= 0.789 //gram per cc
-r= 0.010 //cm
-h= 5.76 //cm
-g= 980.7 // cm /sec^2
+d= 0.789 //density in gram per cc
+r= 0.010 //radius in cm
+h= 5.76 //height in cm
+g= 980.7 //acceleration in cm /sec^2
 
 //Calculations
-R= d*h*r*g/2
+Gamma= d*h*r*g/2
 
 //Results
-mprintf("Surface Tension = %.1f dynes per cm",R);
+mprintf("Surface Tension = %.1f dynes per cm",Gamma);
diff --git a/3876/CH3/EX3.3/Ex3_3.sce b/3876/CH3/EX3.3/Ex3_3.sce
index cef2edbee..0fd2d587f 100644
--- a/3876/CH3/EX3.3/Ex3_3.sce
+++ b/3876/CH3/EX3.3/Ex3_3.sce
@@ -1,17 +1,19 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 3 Liquids
 
 clc;
 clear;
 
 //Initialisation of Variables
-W= 0.220 //gms
-g= 980.7 //cm per sec62
-f= 0.98
-l= 4 //cm
+W= 0.220 //weight in gms
+g= 980.7 //acceleration in cm per sec62
+f= 0.98 //correction factor
+l= 4 //circumference in cm
 
 //Calculations
 T= W*g/(2*l)
-Tc= T*f
+Tc= ceil(T)*f
 
 //Results
 mprintf("Apparent Surface Tension = %.1f dynes per cm",T);
diff --git a/3876/CH3/EX3.4/Ex3_4.sce b/3876/CH3/EX3.4/Ex3_4.sce
index fc11da87a..af0aa0a17 100644
--- a/3876/CH3/EX3.4/Ex3_4.sce
+++ b/3876/CH3/EX3.4/Ex3_4.sce
@@ -1,17 +1,21 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 3 Liquids
 
 clc;
 clear;
 
 //Initialisation of Variables
-n2= 10.05*10**-3 //poise
-d1= 0.879 //gms cm^-3
-t= 88 //sec
-d2= 1 //gms cm^-3
-t1= 120 //sec
+n2= 10.05*10**-3 //absolute viscosity of water in poise
+d1= 0.879 //density in gms cm^-3
+t= 88 //time of flow in sec
+d2= 1 //density in gms cm^-3
+t1= 120 //time of flow in sec
 
 //Calculations
 n1= d1*t/(d2*t1)
 
 //Results
 mprintf("Relative Viscosity= %.3f",n1);
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH4/EX4.1/Ex4_1.sce b/3876/CH4/EX4.1/Ex4_1.sce
index 63fa5d075..f31705560 100644
--- a/3876/CH4/EX4.1/Ex4_1.sce
+++ b/3876/CH4/EX4.1/Ex4_1.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 4 Solutions Nonelectrolytes
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 164.2 //gms
-M= 60 //gms
-V= 0.8 //lit
-d= 1.026 //g/cc
-mw= 18.02 //gms
+m= 164.2 //weight in gms
+M= 60 //weight in gms
+V= 0.8 //volume in litres
+d= 1.026 //density in g/cc
+mw= 18.02 //weight in gms
 
 //CALCULATIONS
 M1= m/M
diff --git a/3876/CH4/EX4.2/Ex4_2.sce b/3876/CH4/EX4.2/Ex4_2.sce
index 49b8d08bd..b7f744aed 100644
--- a/3876/CH4/EX4.2/Ex4_2.sce
+++ b/3876/CH4/EX4.2/Ex4_2.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 4 Solutions Nonelectrolytes
 
@@ -5,11 +7,11 @@ clc;
 clear;
 
 //Initialisation of Variables
-m= 0.0346 //gms
-V= 800 //ml
-P= 742 //mm
-M= 32 //gms
-p= 400 //mm
+m= 0.0346 //weight in gms
+V= 800 //volume in ml
+P= 742 //pressure in mm
+M= 32 //weight in gms
+p= 400 //pressure in mm
 
 //CALCULATIONS
 c= m*1000/V
@@ -22,7 +24,7 @@ c1= k*p
 mprintf("Part (a)")
 mprintf("\nConcentration of oxygen= %.4f gram per litre",c)
 mprintf("\nPart (b)")
-mprintf("\nMoles dissolved = %.4f moles",g)
+mprintf("\nMoles dissolved = %.5f moles",g)
 mprintf("\nPart (c)")
 mprintf("\nBunsen absorption = %.4f litre",K)
 mprintf("\nPart (d)")
@@ -30,3 +32,5 @@ mprintf("\nGrams of oxygen dissolved = %.4f gram per litre",c1)
 mprintf("\nHenry law can be written ")
 cp=c*p/P
 mprintf("%.4f gram per liter",cp)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH4/EX4.3/Ex4_3.sce b/3876/CH4/EX4.3/Ex4_3.sce
index 7b72ce7e2..cac6823a7 100644
--- a/3876/CH4/EX4.3/Ex4_3.sce
+++ b/3876/CH4/EX4.3/Ex4_3.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 4 Solutions Nonelectrolytes
 
 clc;
 clear;
 
 //Initialisation of Variables
-mn= 0.0134 //gms
-mo= 0.0261 //gms
-mh= 0.0081 //gms
-T= 30 //C
-P= 3 //atm
-r= 4/5
+mn= 0.0134 //weight in gms
+mo= 0.0261 //weight in gms
+mh= 0.0081 //weight in gms
+T= 30 //temperature in C
+P= 3 //pressure in atm
+r= 4/5  //ratio of nitrogen to oxygen
 
 //CALCULATIONS
 V= mn*(273+T)*1000/273
diff --git a/3876/CH4/EX4.4/Ex4_4.sce b/3876/CH4/EX4.4/Ex4_4.sce
index d01d55177..922f535c8 100644
--- a/3876/CH4/EX4.4/Ex4_4.sce
+++ b/3876/CH4/EX4.4/Ex4_4.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 4 Solutions Nonelectrolytes
 
 clc;
 clear;
 
 //Initialisation of Variables
-p= 214 //mm
-M= 112.5 //gms
-m= 18 //gms
-m1= 10 //gms
+p= 214 //pressure in mm
+M= 112.5 //weight in gms
+m= 18 //weight in gms
+m1= 10 //weight in gms
 
 //CALCULATIONS
 P= 760-p
diff --git a/3876/CH4/EX4.5/Ex4_5.sce b/3876/CH4/EX4.5/Ex4_5.sce
index 32c60bede..2ca1693e9 100644
--- a/3876/CH4/EX4.5/Ex4_5.sce
+++ b/3876/CH4/EX4.5/Ex4_5.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 4 Solutions Nonelectrolytes
 
@@ -5,10 +7,10 @@ clc;
 clear;
 
 //Initialisation of Variables
-p = 17.4 //mm
-m= 1000 //gms
-M= 18 //gms
-n= 2 //moles
+p = 17.4 //pressure in mm
+m= 1000 //weight in gms
+M= 18 //weight in gms
+n= 2 //no of moles
 
 //CALCULATIONS
 P= p*((m/M)/((m/M)+n))
diff --git a/3876/CH4/EX4.6/Ex4_6.sce b/3876/CH4/EX4.6/Ex4_6.sce
index bf1809d48..08431346b 100644
--- a/3876/CH4/EX4.6/Ex4_6.sce
+++ b/3876/CH4/EX4.6/Ex4_6.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 4 Solutions Nonelectrolytes
 
 clc;
 clear;
 
 //Initialisation of Variables
-m= 92.13 //gms
-M= 78.11 //gms
-n= 1 //moles
-p= 119.6 //mm
-p1= 36.7 //mm
+m= 92.13 //weight in gms
+M= 78.11 //weight in gms
+n= 1 //no of moles
+p= 119.6 //pressure in mm
+p1= 36.7 //pressure in mm
 
 //CALCULATIONS
 n1= m/M
diff --git a/3876/CH5/EX5.1/Ex5_1.sce b/3876/CH5/EX5.1/Ex5_1.sce
index b74f9ef17..2962f0b6d 100644
--- a/3876/CH5/EX5.1/Ex5_1.sce
+++ b/3876/CH5/EX5.1/Ex5_1.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 5 Solutions Osmotic Pressure
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 20 //C
-R= 0.082 //li-atm per mole per degree
-V= 2 //lit
-m= 6 //gms
-M= 60 //gms
+T= 20 ////temperature in Celsius
+R= 0.082 //gas constant in li-atm per mole per degree
+V= 2 //volume in lit
+m= 6 //weight in gms
+M= 60 //weight in gms
 
 //CALCULATIONS
 P= m*R*(273+T)/(M*V)
diff --git a/3876/CH5/EX5.2/Ex5_2.sce b/3876/CH5/EX5.2/Ex5_2.sce
index 09a7e0cc4..344598d41 100644
--- a/3876/CH5/EX5.2/Ex5_2.sce
+++ b/3876/CH5/EX5.2/Ex5_2.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 5 Solutions Osmotic Pressure
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= -0.2 //C
-T1= 25 //C
-T2= 1.86 //C
-R= 0.082 //li-atm per mole per degree
+T= -0.2 //temperature in Celsius
+T1= 25 //temperature in Celsius
+T2= 1.86 //temperature in Celsius
+R= 0.082 //gas constant li-atm per mole per degree
 
 //CALCULATIONS
 P= -T*R*(T1+273)/T2
diff --git a/3876/CH6/EX6.1/Ex6_1.sce b/3876/CH6/EX6.1/Ex6_1.sce
index 4d95d2f33..9b6f2a86c 100644
--- a/3876/CH6/EX6.1/Ex6_1.sce
+++ b/3876/CH6/EX6.1/Ex6_1.sce
@@ -1,18 +1,22 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 6 Solutions of Electrolytes
 
 clc;
 clear;
 
 //Initialisation of Variables
-T= 25 //C
-R= 0.0821 //li-atm per mole per degree
-M= 0.5 //m
-n= 2
-m= 0.680
-V= 1 //lit
+T= 25 //temperature in Celsius
+R= 0.0821 //gas constant li-atm per mole per degree
+M= 0.5 //molality of solution
+n= 2  //for total effective concentration
+m= 0.680  //effective concentration
+V= 1 //volume in litres
 
 //CALCULATIONS
 P= R*(273+T)*M*n*m/V
 
 //RESULTS
 mprintf("Osmotic pressure= %.2f atm",P)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH6/EX6.2/Ex6_2.sce b/3876/CH6/EX6.2/Ex6_2.sce
index 6afd6ddf8..08f25875f 100644
--- a/3876/CH6/EX6.2/Ex6_2.sce
+++ b/3876/CH6/EX6.2/Ex6_2.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 6 Solutions of Electrolytes
 
@@ -5,13 +7,13 @@ clc;
 clear;
 
 //Initialisation of Variables
-Na=0.001 //molar
-NaCl= 0.001 //molar
-BaCl= 0.002 //molar
-Cl= 0.004 //molar
-n= 1 //moles
-n1= 2 //moles
-v= 0.509
+Na=0.001 //solution molarity in Na
+NaCl= 0.001 //solution molarity in NaCl
+BaCl= 0.002 //solution molarity in BaCl
+Cl= 0.004 //solution molarity in Cl
+n= 1 //no of moles
+n1= 2 //no of moles
+v= 0.509 //given
 
 //CALCULATIONS
 Is= 0.5*(Na*n**2+NaCl*n**2+Cl*n**2+BaCl*n1**2)
diff --git a/3876/CH7/EX7.1/Ex7_1.sce b/3876/CH7/EX7.1/Ex7_1.sce
index c0e18cf4c..1e87bf7a4 100644
--- a/3876/CH7/EX7.1/Ex7_1.sce
+++ b/3876/CH7/EX7.1/Ex7_1.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 7 Conductivity
 
 clc;
 clear;
 
 //Initialisation of Variables
-R= 10 //ohms
-V= 5 //v
-t= 20 //min
+R= 10 //resistance in ohms
+V= 5 //potential in v
+t= 20 //time in min
 
 //CALCULATIONS
 I= V/R
diff --git a/3876/CH7/EX7.2/Ex7_2.sce b/3876/CH7/EX7.2/Ex7_2.sce
index 87f1e545d..5394beff0 100644
--- a/3876/CH7/EX7.2/Ex7_2.sce
+++ b/3876/CH7/EX7.2/Ex7_2.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 7 Conductivity
 
@@ -5,16 +7,16 @@ clc;
 clear;
 
 //Initialisation of Variables
-I= 50 //amp
-t= 1 //hr
-F= 96500 //amp-sec
-mh= 1.01 //gms
-mc= 35.46 //gms
-ms= 107.88 //gms
-mb= 79.9 //gms
-mf= 55.85 //gms
-V= 11.2 //lit
-e= 8 //v
+I= 50 //current in amp
+t= 1 //time in hr
+F= 96500 //farads in amp-sec
+mh= 1.01 //weight in gms
+mc= 35.46 //weight in gms
+ms= 107.88 //weight in gms
+mb= 79.9 //weight in gms
+mf= 55.85 //weight in gms
+V= 11.2 //volume in litres
+e= 8 //potential in v
 
 //CALCULATIONS
 N= I*t*60*60/F
@@ -36,3 +38,5 @@ mprintf("\nQuantity of bromine produced= %.2f grams",Mb)
 mprintf("\nQuantity of ferrous ion  produced= %.2f grams",Mf)
 mprintf("\nVolume occupied by gases= %.2f lit",v)
 mprintf("\nEnergy expenditure= %.0f joules or %.2f kilowatt-hour",E,Ee)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH7/EX7.3/Ex7_3.sce b/3876/CH7/EX7.3/Ex7_3.sce
index acb9ba301..836255647 100644
--- a/3876/CH7/EX7.3/Ex7_3.sce
+++ b/3876/CH7/EX7.3/Ex7_3.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 7 Conductivity
 
@@ -5,12 +7,12 @@ clc;
 clear;
 
 //Initialisation of Variables
-i= 20 //amp
-t= 50 ///min
-F= 96500 //coloumb
-we= 8 //gms
-Mo= 32 ///gms
-M= 27 //gms
+i= 20 //current in amp
+t= 50 ///time in min
+F= 96500 //chage in coloumb
+we= 8 //volume in litres
+Mo= 32 //volume in litres
+M= 27 //volume in litres
 n= 3
 
 //CALCULATIONS
diff --git a/3876/CH7/EX7.4/Ex7_4.sce b/3876/CH7/EX7.4/Ex7_4.sce
index 6e81d9e45..9febc7d68 100644
--- a/3876/CH7/EX7.4/Ex7_4.sce
+++ b/3876/CH7/EX7.4/Ex7_4.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 7 Conductivity
 
 clc;
 clear;
 
 //Initialisation of Variables
-L= 0.025 //ohms
-k= 0.0112 //ohms
+L= 0.025 //resistance in ohms
+k= 0.0112 //resistance in ohms
 
 //CALCULATIONS
 C= k/L
diff --git a/3876/CH7/EX7.5/Ex7_5.sce b/3876/CH7/EX7.5/Ex7_5.sce
index 403e63afb..a6e81366e 100644
--- a/3876/CH7/EX7.5/Ex7_5.sce
+++ b/3876/CH7/EX7.5/Ex7_5.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 7 Conductivity
 
@@ -5,11 +7,11 @@ clc;
 clear;
 
 //Initialisation of Variables
-m= 0.01 //M
-CB= 235 //mm
-R= 426.3 //ohms
-M= 265 
-C= 0.448
+m= 0.01 //Molarity
+CB= 235 //pressure in mm
+R= 426.3 //resistance in ohms
+M= 265
+C= 0.448  //cell constant
 
 //CALCULATIONS
 k= M*C/(R*CB)
diff --git a/3876/CH8/EX8.1/Ex8_1.sce b/3876/CH8/EX8.1/Ex8_1.sce
index 513ac80ca..c9e0753d8 100644
--- a/3876/CH8/EX8.1/Ex8_1.sce
+++ b/3876/CH8/EX8.1/Ex8_1.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 8 Chemical Equlibrium
 
 clc;
 clear;
 
 //Initialisation of Variables
-x= 3.33
-n= 5 //moles
+x= 3.33 //no of moles of ester and water
+n= 5 //no of moles
 
 //CALCULATIONS
 N= x**2/(n-x)**2
diff --git a/3876/CH8/EX8.2/Ex8_2.sce b/3876/CH8/EX8.2/Ex8_2.sce
index 49168b979..b7aafd9d2 100644
--- a/3876/CH8/EX8.2/Ex8_2.sce
+++ b/3876/CH8/EX8.2/Ex8_2.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 8 Chemical Equlibrium
 
 clc;
 clear;
 
 //Initialisation of Variables
-n= 1 //mole
-x= 3
-y= 4
+n= 1 //no of moles
+x= 3 //no of moles
+y= 4 //no of moles
 
 //CALCULATIONS
 r= x**2/n**2
diff --git a/3876/CH8/EX8.3/Ex8_3.sce b/3876/CH8/EX8.3/Ex8_3.sce
index 150ddf510..7453e1c94 100644
--- a/3876/CH8/EX8.3/Ex8_3.sce
+++ b/3876/CH8/EX8.3/Ex8_3.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 8 Chemical Equlibrium
 
 clc;
 clear;
 
 //Initialisation of Variables
-k= 1.1*10**-5
-V= 600 //ml
-n= 0.4 //mole
+k= 1.1*10**-5 //dissociation constant
+V= 600 //volume in ml
+n= 0.4 //no of mole
 
 //CALCULATIONS
 m= n*1000/V
diff --git a/3876/CH8/EX8.4/Ex8_4.sce b/3876/CH8/EX8.4/Ex8_4.sce
index 8d0874e4c..0386ca125 100644
--- a/3876/CH8/EX8.4/Ex8_4.sce
+++ b/3876/CH8/EX8.4/Ex8_4.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 8 Chemical Equlibrium
 
@@ -5,9 +7,9 @@ clc;
 clear;
 
 //Initialisation of Variables
-pno2= 0.31 //atm
-pn2o2= 0.69 //atm
-p= 10 //atm
+pno2= 0.31 //pressure in atm
+pn2o2= 0.69 //pressure in atm
+p= 10 //pressure in atm
 
 //CALCULATIONS
 Kp= pno2**2/pn2o2
diff --git a/3876/CH8/EX8.5/Ex8_5.sce b/3876/CH8/EX8.5/Ex8_5.sce
index d740feebe..539f942c9 100644
--- a/3876/CH8/EX8.5/Ex8_5.sce
+++ b/3876/CH8/EX8.5/Ex8_5.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 8 Chemical Equlibrium
 
@@ -5,11 +7,11 @@ clc;
 clear;
 
 //Initialisation of Variables
-T= 65 //C
+T= 65 //temperature in Celsius
 R= 1.98 //cal/mol K
-kp= 2.8
-kp1= 0.141
-T1= 25 //C
+kp= 2.8  //at 65 degrees clesius
+kp1= 0.141  //at 25 degrees clesius
+T1= 25 //temperature in Celsius
 
 //CALCULATIONS
 H= log10(kp/kp1)*2.303*R*(273+T1)*(273+T)/(T-T1)
diff --git a/3876/CH9/EX9.1/Ex9_1.sce b/3876/CH9/EX9.1/Ex9_1.sce
index e2fb10cb8..a9d607ae5 100644
--- a/3876/CH9/EX9.1/Ex9_1.sce
+++ b/3876/CH9/EX9.1/Ex9_1.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 0.1 //M
-p= 1.34 //per cent
-T= 25 //C
+c= 0.1 //Molarity of solution
+p= 1.34 //per cent ionized
+T= 25 //temperature in Celsius
 
 //CALCULATIONS
 C1= c*p/100
diff --git a/3876/CH9/EX9.10/Ex9_10.sce b/3876/CH9/EX9.10/Ex9_10.sce
index 205bf5839..563817042 100644
--- a/3876/CH9/EX9.10/Ex9_10.sce
+++ b/3876/CH9/EX9.10/Ex9_10.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 0.1 //M
-Kb= 1.8*10**-5
-Kw= 10**-14
+c= 0.1 //Molarity of solution
+Kb= 1.8*10**-5  //given
+Kw= 10**-14  //from hydrolysis constant expression
 
 //CALCULATIONS
 C= sqrt(c*Kw/Kb)
diff --git a/3876/CH9/EX9.11/Ex9_11.sce b/3876/CH9/EX9.11/Ex9_11.sce
index be2d7804b..d23364e8d 100644
--- a/3876/CH9/EX9.11/Ex9_11.sce
+++ b/3876/CH9/EX9.11/Ex9_11.sce
@@ -1,16 +1,18 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 0.050 //M
-Kb= 1.8*10**-5
-T= 25 //C
-Kw= 10**-14
+c= 0.050 //Molarity of solution
+Kb= 1.8*10**-5  //given
+T= 25 //temperature in Celsius
+Kw= 10**-14  //from hydrolysis constant expression
 
 //CALCULATIONS
 C= sqrt(Kw*c/Kb)
 
 //RESULTS
-mprintf("Concentration of hydronium ion = %.2e mol per litre",C)
+mprintf("Concentration of hydronium ion = %.1e mol per litre",C)
diff --git a/3876/CH9/EX9.12/Ex9_12.sce b/3876/CH9/EX9.12/Ex9_12.sce
index eebe72080..338bbd1e7 100644
--- a/3876/CH9/EX9.12/Ex9_12.sce
+++ b/3876/CH9/EX9.12/Ex9_12.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-kw= 10**-14
-Ka= 1.8*10**-5
+kw= 10**-14  //from hydrolysis constant expression
+Ka= 1.8*10**-5  //given
 
 //CALCULATIONS
 Kb= Ka
diff --git a/3876/CH9/EX9.13/Ex9_13.sce b/3876/CH9/EX9.13/Ex9_13.sce
index 7eb01ba6a..3217edf0e 100644
--- a/3876/CH9/EX9.13/Ex9_13.sce
+++ b/3876/CH9/EX9.13/Ex9_13.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-k1= 3.5*10**-7
-k2= 4.4*10**-11
+k1= 3.5*10**-7  //given
+k2= 4.4*10**-11  //given
 
 //CALCULATIONS
 c= sqrt(k1*k2)
diff --git a/3876/CH9/EX9.14/Ex9_14.sce b/3876/CH9/EX9.14/Ex9_14.sce
index fadadb780..c45653aef 100644
--- a/3876/CH9/EX9.14/Ex9_14.sce
+++ b/3876/CH9/EX9.14/Ex9_14.sce
@@ -1,10 +1,12 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 1.92*10**-5 //mole per litre
+c= 1.92*10**-5 //concentration mole per litre
 
 //CALCULATIONS
 pH= -log10(c)
diff --git a/3876/CH9/EX9.15/Ex9_15.sce b/3876/CH9/EX9.15/Ex9_15.sce
index 3c8c017b4..13f72f114 100644
--- a/3876/CH9/EX9.15/Ex9_15.sce
+++ b/3876/CH9/EX9.15/Ex9_15.sce
@@ -1,10 +1,12 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-pH= 7.36
+pH= 7.36  //given
 
 //CALCULATIONS
 C= 10**-pH
diff --git a/3876/CH9/EX9.16/Ex9_16.sce b/3876/CH9/EX9.16/Ex9_16.sce
index ef63ef67d..7f1bbb1d1 100644
--- a/3876/CH9/EX9.16/Ex9_16.sce
+++ b/3876/CH9/EX9.16/Ex9_16.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 1 //M
-Kb= 5.3*10**-5
+c= 1 //Molarity of solution
+Kb= 5.3*10**-5  //given
 pKw= 14
 
 //CALCULATIONS
diff --git a/3876/CH9/EX9.17/Ex9_17.sce b/3876/CH9/EX9.17/Ex9_17.sce
index c8ea4479e..a937ae79c 100644
--- a/3876/CH9/EX9.17/Ex9_17.sce
+++ b/3876/CH9/EX9.17/Ex9_17.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 0.1 //M
-Ka= 6.3*10**-5
+c= 0.1 //Molarity of solution
+Ka= 6.3*10**-5 //given
 pKw= 14
 //CALCULATIONS
 pH= -0.5*log10(Ka)+0.5*pKw+0.5*log10(c)
diff --git a/3876/CH9/EX9.18/Ex9_18.sce b/3876/CH9/EX9.18/Ex9_18.sce
index ad0d0ade0..65d4cdf75 100644
--- a/3876/CH9/EX9.18/Ex9_18.sce
+++ b/3876/CH9/EX9.18/Ex9_18.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-Ka= 1.8*10**-5
-a= 0.1 //molar
+Ka= 1.8*10**-5  //given
+a= 0.1 //concentration in mole per liter
 
 //CALCULATIONS
 pH= -log10(Ka)
diff --git a/3876/CH9/EX9.19/Ex9_19.sce b/3876/CH9/EX9.19/Ex9_19.sce
index f27fc7b75..484dd9179 100644
--- a/3876/CH9/EX9.19/Ex9_19.sce
+++ b/3876/CH9/EX9.19/Ex9_19.sce
@@ -1,14 +1,16 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-pH= 7.10
-pH1= 7.21
+pH= 7.10  //given
+pKa= 7.21  //given
 
 //CALCULATIONS
-r= 10**(pH-pH1)
+r= 10**(pH-pKa)
 
 //RESULTS
-mprintf("Ratio of salt to acid = %.2f",r)
+mprintf("Ratio of salt to acid = %.3f",r)
diff --git a/3876/CH9/EX9.2/Ex9_2.sce b/3876/CH9/EX9.2/Ex9_2.sce
index 66f93c345..2a58c01f4 100644
--- a/3876/CH9/EX9.2/Ex9_2.sce
+++ b/3876/CH9/EX9.2/Ex9_2.sce
@@ -1,15 +1,17 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-k= 1.8*10**-5
-C= 0.2 //M
-T= 25 //C
+Ka= 1.8*10**-5  //ionization constant
+C= 0.2 //Molarity of solution
+T= 25 //temperature in Celsius
 
 //CALCULATIONS
-x= sqrt(C*k)
+x= sqrt(C*Ka)
 a= x/C
 C1= a*C
 
diff --git a/3876/CH9/EX9.3/Ex9_3.sce b/3876/CH9/EX9.3/Ex9_3.sce
index 6e0cefb21..d9aaf3cf1 100644
--- a/3876/CH9/EX9.3/Ex9_3.sce
+++ b/3876/CH9/EX9.3/Ex9_3.sce
@@ -1,13 +1,15 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-K= 1.8*10**-5
-V= 500 //ml
-c1= 0.3 //M
-c2= 0.2 //M
+K= 1.8*10**-5  //ionization constant
+V= 500 //volume in ml
+c1= 0.3 //Molarity of solution
+c2= 0.2 //Molarity of solution
 
 //CALCULATIONS
 x= V*c1/1000
diff --git a/3876/CH9/EX9.4/Ex9_4.sce b/3876/CH9/EX9.4/Ex9_4.sce
index 8a8068362..9006187ff 100644
--- a/3876/CH9/EX9.4/Ex9_4.sce
+++ b/3876/CH9/EX9.4/Ex9_4.sce
@@ -1,21 +1,23 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-K= 1.4*10**-5
-T= 25 //C
-V= 200 //ml
-m= 3.7 //gms
-m1= 4.8 //gms
-M= 74 //gms
-M1= 96 //gms
+Ka= 1.4*10**-5
+T= 25 //temperature in Celsius
+V= 200 //volume in millilitres
+m= 3.7 //weight in gms
+m1= 4.8 //weight in gms
+M= 74 //weight in gms
+M1= 96 //weight in gms
 
 //CALCULATIONS
 x= m*1000/(V*M)
 y= m1*1000/(V*M1)
-X= K*x/y
+X= Ka*x/y
 
 //RESULTS
 mprintf("hydronium-ion concentration = %.2e mole per litre",X)
diff --git a/3876/CH9/EX9.5/Ex9_5.sce b/3876/CH9/EX9.5/Ex9_5.sce
index 2dec9f077..04d7b1576 100644
--- a/3876/CH9/EX9.5/Ex9_5.sce
+++ b/3876/CH9/EX9.5/Ex9_5.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-c= 0.050 //M
-Ksp= 4.3*10**-7
+c= 0.050 //Molarity of solution
+Ksp= 4.3*10**-7   //using ionization expression
 
 //CALCULATIONS
 C= sqrt(Ksp*c)
diff --git a/3876/CH9/EX9.6/Ex9_6.sce b/3876/CH9/EX9.6/Ex9_6.sce
index aa6cb2d9e..aaaf9fbab 100644
--- a/3876/CH9/EX9.6/Ex9_6.sce
+++ b/3876/CH9/EX9.6/Ex9_6.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-C= 0.050 //M
-K= 2.4*10**-17
-c= 0.1 //M
+C= 0.050 //Molarity of solution
+K= 2.4*10**-17   //constant
+c= 0.1 //Molarity of solution
 
 //CALCULATIONS
 c1= K*C/c**2
diff --git a/3876/CH9/EX9.7/Ex9_7.sce b/3876/CH9/EX9.7/Ex9_7.sce
index c1d464999..e2cacbe72 100644
--- a/3876/CH9/EX9.7/Ex9_7.sce
+++ b/3876/CH9/EX9.7/Ex9_7.sce
@@ -1,11 +1,13 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-n= 1.31*10**-4 //mole
-T= 25 //C
+n= 1.31*10**-4 //mole of silver chromate
+T= 25 //temperature in Celsius
 
 //CALCULATIONS
 N= 2*n
diff --git a/3876/CH9/EX9.8/Ex9_8.sce b/3876/CH9/EX9.8/Ex9_8.sce
index 479550272..a5174d146 100644
--- a/3876/CH9/EX9.8/Ex9_8.sce
+++ b/3876/CH9/EX9.8/Ex9_8.sce
@@ -1,12 +1,14 @@
+//Windows 10
+// Scilab 6.0.0
 //Chapter 9 Ionic Equilibria and Buffer Action
 
 clc;
 clear;
 
 //Initialisation of Variables
-Ksp= 1.4*10**-11
-V= 200 //ml
-M= 24.3 ///gms
+Ksp= 1.4*10**-11  //given
+V= 200 //volume in ml
+M= 24.3 //weight in gms
 
 //CALCULATIONS
 x= (Ksp/4)**(1/3)
@@ -14,3 +16,5 @@ m= x*M*V/1000
 
 //RESULTS
 mprintf("Grams of Mg+2 present = %.1e gms per mol",m)
+
+//The difference in the solution compared to textbook is due to round off error
diff --git a/3876/CH9/EX9.9/Ex9_9.sce b/3876/CH9/EX9.9/Ex9_9.sce
index 2cce2a7c9..741e82e27 100644
--- a/3876/CH9/EX9.9/Ex9_9.sce
+++ b/3876/CH9/EX9.9/Ex9_9.sce
@@ -1,3 +1,5 @@
+//Windows 10
+// Scilab 6.0.0
 
 //Chapter 9 Ionic Equilibria and Buffer Action
 
@@ -5,10 +7,10 @@ clc;
 clear;
 
 //Initialisation of Variables
-c= 0.010 //M
-Ksp= 1.56*10**-10
-M= 108 //gms
-C= 10**-3 //M
+c= 0.010 //Molarity of solution
+Ksp= 1.56*10**-10  //given
+M= 108 //weight in gms
+C= 10**-3 //Molarity of solution
 
 //CALCULATIONS
 K= Ksp/C