initial commit / add all books

44 files changed, 430 insertions, 0 deletions

diff --git a/1427/CH18/EX18.1/18_1.sce b/1427/CH18/EX18.1/18_1.sce
new file mode 100644
index 000000000..833a292b2
--- /dev/null
+++ b/1427/CH18/EX18.1/18_1.sce
@@ -0,0 +1,8 @@
+//ques-18.1

+//Calculating heat of formation of ethyl alcohol

+clc

+h1=-333;//heat of combustion of ethyl alcohol (in kcal)

+h2=-94.3;//heat of formation of carbon dioxide (in kcal)

+h3=-68.5;//heat of formation of water (in kcal)

+H=2*h2+3*h3-h1;//heat of formation of ethyl alcohol (in kcal)

+printf("Heat of formation of ethyl alcohol is %.1f kcal.",H);

diff --git a/1427/CH18/EX18.10/18_10.sce b/1427/CH18/EX18.10/18_10.sce
new file mode 100644
index 000000000..63b84440e
--- /dev/null
+++ b/1427/CH18/EX18.10/18_10.sce
@@ -0,0 +1,9 @@
+//ques-18.10

+//Calculating work done and heat rejected and efficiency

+clc

+T1=0; T2=100;//temperature (in degree celsius)

+q2=840;//energy absorbed (in J)

+q1=q2*((T1+273)/(T2+273));//heat rejected (in J)

+W=q2-q1;//work done (in J)

+n=(T2-T1)/(T2+273);//efficiency

+printf("The work done is %.1f J, heat rejected is %.1f J and efficiency is %.3f.",W,q1,n);

diff --git a/1427/CH18/EX18.11/18_11.sce b/1427/CH18/EX18.11/18_11.sce
new file mode 100644
index 000000000..da5e0a394
--- /dev/null
+++ b/1427/CH18/EX18.11/18_11.sce
@@ -0,0 +1,7 @@
+//ques-18.11

+//Calculating heat to be withdrawn from reservoir

+clc

+n=0.42;//efficiency

+w=203;//work done (in cal)

+q2=w/n;//heat withdrawn (in cal)

+printf("Heat withdrawn from reservoir is %.1f cal.",q2);

diff --git a/1427/CH18/EX18.12/18_12.sce b/1427/CH18/EX18.12/18_12.sce
new file mode 100644
index 000000000..52326a158
--- /dev/null
+++ b/1427/CH18/EX18.12/18_12.sce
@@ -0,0 +1,6 @@
+//ques-18.12

+//Determining required percentage for a heat engine

+clc

+n=0.1;//(T2-T1)/T2

+r=0.9;//T1/T2

+printf("Required percentage of T1/T2 is %d.",r*100);

diff --git a/1427/CH18/EX18.13/18_13.sce b/1427/CH18/EX18.13/18_13.sce
new file mode 100644
index 000000000..f4aeb396c
--- /dev/null
+++ b/1427/CH18/EX18.13/18_13.sce
@@ -0,0 +1,8 @@
+//ques-18.13

+//Calculating change in entropy for an isothermal expansion

+clc

+n=5;//moles of gas

+//r=V2/V1

+r=6;

+S=2.303*8.314*n*log10(r);//change in entropy

+printf("The change in entropy is %.1f J/K.",S);

diff --git a/1427/CH18/EX18.14/18_14.sce b/1427/CH18/EX18.14/18_14.sce
new file mode 100644
index 000000000..6e84aabb3
--- /dev/null
+++ b/1427/CH18/EX18.14/18_14.sce
@@ -0,0 +1,9 @@
+//ques-18.14

+//Calculating increase in entropy in evaporation of water

+clc

+n=1;//moles of water

+L=540;//latent heat of vapourosation (in cal/g)

+T=100;//temperature (in degree celsius)

+q=L*n*18;//heat (reversible)

+S=q/(T+273);//increase in entropy

+printf("The increase in entropy is %.3f cal/mol/K.",S);

diff --git a/1427/CH18/EX18.15/18_15.sce b/1427/CH18/EX18.15/18_15.sce
new file mode 100644
index 000000000..4d9e8eaf3
--- /dev/null
+++ b/1427/CH18/EX18.15/18_15.sce
@@ -0,0 +1,9 @@
+//ques-18.15

+//Calculating entropy of mixing per mole of the mixture

+clc

+n1=1;//mole sof hydrogen

+n2=9;//moles of nitrogen

+x1=n1/(n1+n2);

+x2=n2/(n1+n2);

+S=-8.314*2.303*(x1*log10(x1)+x2*log10(x2));//entropy of mixing

+printf("The entropy of mixing is %.3f J/K/mol.",S);

diff --git a/1427/CH18/EX18.16/18_16.sce b/1427/CH18/EX18.16/18_16.sce
new file mode 100644
index 000000000..0e1b7a81a
--- /dev/null
+++ b/1427/CH18/EX18.16/18_16.sce
@@ -0,0 +1,9 @@
+//ques-18.16

+//Calculating increase in entropy

+clc

+v1=2.8;//volume of O2 (in L)

+v2=19.6;//volume of H2 (in L)

+n1=v1/22.4; n2=v2/22.4;//(in moles)

+x1=n1/(n1+n2); x2=n2/(n1+n2);

+S=-8.314*2.303*(x1*log10(x1)+x2*log10(x2));

+printf("The increase in entropy is %.3f J/K.",S);

diff --git a/1427/CH18/EX18.18/18_18.sce b/1427/CH18/EX18.18/18_18.sce
new file mode 100644
index 000000000..9a90e0dfc
--- /dev/null
+++ b/1427/CH18/EX18.18/18_18.sce
@@ -0,0 +1,9 @@
+//ques-18.18

+//Calculating entropy change and free energy change of the reaction

+clc

+T1=300; T2=330;//temperature (in K)

+G1=-16;//free energy change (in kcal)

+H=-10;//enthalpy change (in kcal)

+S=(H-G1)/T1;//entropy change (in kcal/K)

+G2=H-T2*S;//free energy change (in kcal)

+printf("The entropy change is %d cal/K and free energy change at 330K is %.1f kcal.",S*1000,G2);

diff --git a/1427/CH18/EX18.19/18_19.sce b/1427/CH18/EX18.19/18_19.sce
new file mode 100644
index 000000000..fce0d427d
--- /dev/null
+++ b/1427/CH18/EX18.19/18_19.sce
@@ -0,0 +1,9 @@
+//ques-18.19

+//Calculating enthalpy change for the process

+clc

+G1=-85.77; G2=-83.68;//free energy change (in kJ)

+T1=273+25; T2=273+35;//temperature (in K)

+//G=H-T*S

+//On comparing, (G1-H)/T1 = (G2-H)/T2

+H=-148;//enthalpy change (in kJ)

+printf("The enthalpy change for the process is %d kJ.",H);

diff --git a/1427/CH18/EX18.2/18_2.sce b/1427/CH18/EX18.2/18_2.sce
new file mode 100644
index 000000000..b56d906d1
--- /dev/null
+++ b/1427/CH18/EX18.2/18_2.sce
@@ -0,0 +1,8 @@
+//ques-18.2

+//Calculating enthalpy of formation of benzene

+clc

+h1=-3273;//heat of combustion of benzene (in kJ)

+h2=-394;//heat of formation of carbon dioxide (in kJ)

+h3=-286;//heat of formation of water (in kJ)

+H=6*h2+3*h3-h1;//enthalpy of formation of benzene (in kJ)

+printf("Enthalpy of formation of benzene is %.0f kJ/mol.",H);

diff --git a/1427/CH18/EX18.20/18_20.sce b/1427/CH18/EX18.20/18_20.sce
new file mode 100644
index 000000000..b9c55838f
--- /dev/null
+++ b/1427/CH18/EX18.20/18_20.sce
@@ -0,0 +1,12 @@
+//ques-18.20

+//Calculating standard heat of formation and total change in heat capacities at constant pressure

+clc

+T1=273+25; T2=273+20;//temperature (in K)

+//C = molar heat capacities at constant pressure (in cal/degree/mole)

+C1=6.89;//hydrogen

+C2=6.97;//oxygen

+C3=8;//water

+H1=-68.3;//enthalpy change (in kcal/mol)

+Cp=C3-C1+C2/2;

+H2=H1*1000+(T2-T1)*Cp;//enthalpy change (in kcal/mol)

+printf("The standard heat of formation is %d kcal/mol and total change in heat capacities at constant pressure is %.3f kcal/mol.",H1,H2/1000);

diff --git a/1427/CH18/EX18.21/18_21.sce b/1427/CH18/EX18.21/18_21.sce
new file mode 100644
index 000000000..ed531fd9a
--- /dev/null
+++ b/1427/CH18/EX18.21/18_21.sce
@@ -0,0 +1,8 @@
+//ques-18.21

+//Determining heat of formation at constant volume

+clc

+H=-74.85;//heat of formation of methane at constant pressure (in kJ/mol)

+n=1-2;//change in gaseous moles

+T=273+25;//temperature (in K)

+U=H*1000-n*8.314*T;//heat of formation at constant volume

+printf("Heat of formation at constant volume is %.2f kJ/mol.",U/1000);

diff --git a/1427/CH18/EX18.22/18_22.sce b/1427/CH18/EX18.22/18_22.sce
new file mode 100644
index 000000000..7201cea7c
--- /dev/null
+++ b/1427/CH18/EX18.22/18_22.sce
@@ -0,0 +1,14 @@
+//ques-18.22

+//Calculating enthalpy change and entropy change and free energy change and internal energy change

+clc

+P=1;//pressure (in atm)

+L=540;//latent heat of vapourisation of water (in cal/g)

+T1=273+0; T2=273+100;//temperature (in K)

+n=1;//moles of water

+H=n*18*L;//enthalpy change (in cal)

+S=H/T2;//entropy change (in cal/K)

+G=H-T2*S;//free energy change (in cal)

+V1=18;//volume of water at T1 (in mL)

+V2=(V1*T2)/T1;////volume of water at T2 (in mL)

+U=H-P*(V2-V1);//internal energy change (in cal)

+printf("The enthalpy change is %.2f kcal, entropy change is %.2f cal/K, free energy change is %d and internal energy change is %.4f kcal.",H/1000,S,G,U/1000);

diff --git a/1427/CH18/EX18.23/18_23.sce b/1427/CH18/EX18.23/18_23.sce
new file mode 100644
index 000000000..277ea561a
--- /dev/null
+++ b/1427/CH18/EX18.23/18_23.sce
@@ -0,0 +1,9 @@
+//ques-18.23

+//Calculating standard free energy change for the reaction

+clc

+//G = free energy (in kJ/mol)

+G1=-16.8;//ammonia

+G2=-86.7;//NO

+G3=-237.2;//water

+G=G2+G3*(1.5)-G1;//free energy change

+printf("The free energy change required is %.1f kJ/mol.",G);

diff --git a/1427/CH18/EX18.24/18_24.sce b/1427/CH18/EX18.24/18_24.sce
new file mode 100644
index 000000000..ebaa7a33f
--- /dev/null
+++ b/1427/CH18/EX18.24/18_24.sce
@@ -0,0 +1,10 @@
+//ques-18.24

+//Finding vapour pressure of benzene at 300 K

+clc

+Hv=7413;//latent heat of vapourization (in cal/mol)

+T1=273+80; T2=273+27;//temperature (in K)

+P1=760;//mm Hg

+R=1.987;//cal/mol/K

+//On solving, log(P2/P1) = (Hv*(T2-T1))/(2.303*R*T1*T2)

+P2=P1/6.467;

+printf("The required vapour pressure is %.2f mm Hg.",P2);

diff --git a/1427/CH18/EX18.25/18_25.sce b/1427/CH18/EX18.25/18_25.sce
new file mode 100644
index 000000000..9c74e2157
--- /dev/null
+++ b/1427/CH18/EX18.25/18_25.sce
@@ -0,0 +1,10 @@
+//ques-18.25

+//Calculating pressure at which water must be heated to produce superheated steam

+clc

+Hv=540;//latent heat of vapourization (in cal/g)

+T1=273+100; T2=273+150;//temperature (in K)

+P1=1;//in atm

+R=1.987;//cal/mol/K

+//On solving, log(P2/P1) = (Hv*(T2-T1))/(2.303*R*T1*T2)

+P2=P1*4.709

+printf("The required vapour pressure is %.3f atm.",P2);

diff --git a/1427/CH18/EX18.26/18_26.sce b/1427/CH18/EX18.26/18_26.sce
new file mode 100644
index 000000000..871b9b48a
--- /dev/null
+++ b/1427/CH18/EX18.26/18_26.sce
@@ -0,0 +1,12 @@
+//ques-18.26

+//Calculating free energy change at 298 K

+clc

+T=298;//temperature (in K)

+S=-10.5;//entropy change (in cal/K)

+U=-2500;//internal energy change (in cal/K)

+R=1.987;//cal/mol/K

+n=2-(2+1);//difference in moles of gases

+//G=H-T*S

+//H=U+n*R*T

+G=U+n*R*T-T*S;//free energy change

+printf("The free energy change is %.0f cal.",G);

diff --git a/1427/CH18/EX18.27/18_27.sce b/1427/CH18/EX18.27/18_27.sce
new file mode 100644
index 000000000..170c55eeb
--- /dev/null
+++ b/1427/CH18/EX18.27/18_27.sce
@@ -0,0 +1,11 @@
+//ques-18.27

+//Finding partial pressure of hydrogen at which free energy change is zero

+clc

+G=-10.1;//free energy change (in kJ/mol)

+T=500;//temperature (in K)

+p1=10;//partial pressure of HI (in atm)

+p2=0.001;//partial pressure of I2 (in atm)

+//On solving, log10(K) = (-G)/(2.303*8.314*T)

+K=11.36;

+p3=(p1/(K*sqrt(p2)))^2;

+printf("The partial pressure of hydrogen is %.0f atm.",p3);

diff --git a/1427/CH18/EX18.28/18_28.sce b/1427/CH18/EX18.28/18_28.sce
new file mode 100644
index 000000000..540ba6898
--- /dev/null
+++ b/1427/CH18/EX18.28/18_28.sce
@@ -0,0 +1,8 @@
+//ques-18.28

+//Calculating heat of reaction in terms of calories

+clc

+K1=1.64*10^-4; K2=0.144*10^-4;//equilibrium constant (in atm)

+T1=273+400; T2=273+500;//temperature (in K)

+R=1.987;//cal/mol/K

+H=(log10(K2/K1)*2.303*R*T1*T2)/(T2-T1);

+printf("The heat of the reaction is %.2f kcal/mol.",H/1000);

diff --git a/1427/CH18/EX18.29/18_29.sce b/1427/CH18/EX18.29/18_29.sce
new file mode 100644
index 000000000..02926a1c0
--- /dev/null
+++ b/1427/CH18/EX18.29/18_29.sce
@@ -0,0 +1,8 @@
+//ques-18.29

+//Determining temperature at which water will boil when atmospheric pressure is 528mm Hg

+clc

+P1=528; P2=760;//pressure (in mm Hg)

+H=545.5;//latent heat of vapourisation (in cal/g)

+T2=273+100;//temperature (in K)

+T1=1/((log10(P2/P1)*2.303*1.987)/(H*18)+(1/T2));

+printf("The temperature required is %.0f K.",T1);

diff --git a/1427/CH18/EX18.3/18_3.sce b/1427/CH18/EX18.3/18_3.sce
new file mode 100644
index 000000000..a07a4d88f
--- /dev/null
+++ b/1427/CH18/EX18.3/18_3.sce
@@ -0,0 +1,8 @@
+//ques-18.3

+//Calculating heat of a reaction

+clc

+h1=-110.5;//heat of formation of carbon monoxide (in kJ)

+h2=-393.8;//heat of formation of carbon dioxide (in kJ)

+h3=-241.8;//heat of formation of water (in kJ)

+H=h1-h2+h3;//heat of reaction (in kJ)

+printf("Heat of the given reaction is %.1f kJ.",H);

diff --git a/1427/CH18/EX18.30/18_30.sce b/1427/CH18/EX18.30/18_30.sce
new file mode 100644
index 000000000..d37a6decb
--- /dev/null
+++ b/1427/CH18/EX18.30/18_30.sce
@@ -0,0 +1,14 @@
+//ques-18.30

+//Calculating equilibrium constant for the given reaction

+clc

+T=278;//temperature (in K)

+S=-333.3;//entropy change (in J/K/mol)

+R=8.31;// J/K/mol

+h1=-110.5;//heat of formation for CO (in kJ/mol)

+h2=-74.8;//heat of formation for methane (in kJ/mol)

+h3=-286;//heat of formation for water (in kJ/mol)

+H=h2+h3-h1;//enthalpy change (in kJ/mol)

+G=(H*1000)-T*S;//free energy change (in kJ/mol)

+//On solving, log10(K) = -G/(2.303*R*T)

+K=2.97;//(*10^26)

+printf("The equilibrium constant required is %.2f*10^26.",K);

diff --git a/1427/CH18/EX18.31/18_31.sce b/1427/CH18/EX18.31/18_31.sce
new file mode 100644
index 000000000..82aa1ca8e
--- /dev/null
+++ b/1427/CH18/EX18.31/18_31.sce
@@ -0,0 +1,10 @@
+//ques-18.31

+//Calculating entropy change in given state of system

+clc

+n=1;//moles of ideal gas

+Cv=12.55;//calorific volume (in J/K/mol)

+T1=298; T2=233;//temperature (in K)

+P1=2; P2=0.4;//pressure (in atm)

+R=8.314;//in J/K/mol

+S=n*Cv*log(T2/T1)-n*R*log(P2/P1);

+printf("The entropy change is %.3f J/K/mol.",S);

diff --git a/1427/CH18/EX18.32/18_32.sce b/1427/CH18/EX18.32/18_32.sce
new file mode 100644
index 000000000..e0d705d78
--- /dev/null
+++ b/1427/CH18/EX18.32/18_32.sce
@@ -0,0 +1,13 @@
+//ques-18.32

+//Calculating entropy change when pressure is kept constant and when volume is kept constant

+clc

+n=1;//moles of ideal gas

+Cv=12.471;//calorific volume (in J/K/mol)

+T1=300; T2=600;//temperature (in K)

+R=8.314;//in J/K/mol

+//Pressure is constant

+Cp=Cv+R;//calorific pressure (in J/K/mol)

+S_P=2.303*n*Cp*log10(T2/T1);

+//Volume is constant

+S_V=2.303*n*Cv*log10(T2/T1);

+printf("The entropy change when pressure is kept constant is %.3f J/K/mol and when volume is kept constant is %.3f J/K/mol.",S_P,S_V);

diff --git a/1427/CH18/EX18.34/18_34.sce b/1427/CH18/EX18.34/18_34.sce
new file mode 100644
index 000000000..a3a8c3838
--- /dev/null
+++ b/1427/CH18/EX18.34/18_34.sce
@@ -0,0 +1,8 @@
+//ques-18.34

+//Computing free energy change

+clc

+n=5;//moles of ideal gas

+T=273+27;//temperature (in K)

+V1=50; V2=1000;//volume (in L)

+G=2.303*n*8.314*T*log10(V1/V2);

+printf("The free energy change is %.3f kJ.",G/1000);

diff --git a/1427/CH18/EX18.35/18_35.sce b/1427/CH18/EX18.35/18_35.sce
new file mode 100644
index 000000000..a3ba76ede
--- /dev/null
+++ b/1427/CH18/EX18.35/18_35.sce
@@ -0,0 +1,13 @@
+//ques-18.35

+//Calculating q w U H G and A

+clc

+n=1;//moles of ideal gas

+V1=5; V2=10;//volume (in L)

+T=300;//temperature (in K)

+U=0;//for isothemal and reversible process

+H=0;//for isothemal and reversible process

+G=-n*8.314*T*log(V2/V1);

+A=G;

+w=-G;

+q=w;

+printf("q=w=%.0f J/mol, U=H=0, G=A=%.0f J/mol.",q,A);

diff --git a/1427/CH18/EX18.36/18_36.sce b/1427/CH18/EX18.36/18_36.sce
new file mode 100644
index 000000000..9938dc2d1
--- /dev/null
+++ b/1427/CH18/EX18.36/18_36.sce
@@ -0,0 +1,15 @@
+//ques-18.36

+//Calculating w q U H G A and S

+clc

+T=373;//boiling point of water (in K)

+P=1;//pressure (in atm)

+L=40.67;//latent heat of vapourisation (in kJ/mol)

+R=8.314;//in J/K/mol

+w=-R*T/1000;

+H=-L;

+q=H;

+U=H-w;

+G=0;

+A=-w;

+S=-(q*1000)/T;

+printf("w=%.1f kJ/mol, q=H=%.2f kJ/mol, U=%.2f kJ/mol, G=%d; A=%.1f kJ/mol and S=%.0f J/K/mol.",w,q,U,G,A,S);

diff --git a/1427/CH18/EX18.37/18_37.sce b/1427/CH18/EX18.37/18_37.sce
new file mode 100644
index 000000000..8fb61c2f5
--- /dev/null
+++ b/1427/CH18/EX18.37/18_37.sce
@@ -0,0 +1,8 @@
+//ques-18.37

+//Calculating final temperature of the gas

+clc

+q=1.42;

+r=20;//ratio = P2/P1

+T1=273;//initial temperature (in K)

+T2=T1/(r^((1-q)/q));

+printf("Final temperature is %.1f K.",T2);

diff --git a/1427/CH18/EX18.38/18_38.sce b/1427/CH18/EX18.38/18_38.sce
new file mode 100644
index 000000000..ffc0dc063
--- /dev/null
+++ b/1427/CH18/EX18.38/18_38.sce
@@ -0,0 +1,14 @@
+//ques-18.38

+//Calculating S and A and G for vaporization of benzene

+clc

+n=2;//moles of benzene

+T=273+80.2;//boiling point (in K)

+g=78;//molar weight of benzene (in g)

+Lv=101;//latent heat of vaporization (in cal/g)

+U=n*g*Lv;

+H=U;

+S=H/T;

+G=H-T*S;

+A=G;

+printf("The entropy change is %.1f cal/K and A=G=%d.",S,A);

+ 

diff --git a/1427/CH18/EX18.39/18_39.sce b/1427/CH18/EX18.39/18_39.sce
new file mode 100644
index 000000000..963c1976d
--- /dev/null
+++ b/1427/CH18/EX18.39/18_39.sce
@@ -0,0 +1,14 @@
+//ques-18.39

+//Calculating values of q and w and U for conversion of water to steam

+clc

+n=1;//moles of water

+P=1;//pressure (in atm)

+L=540;//latent heat of steam (in cal/g)

+T1=273; T2=373;//temperature (in K)

+V1=22.4;//volume (in L)

+q=n*18*L;

+V2=(V1*T2)/T1;

+w=-P*V2;//neglecting V1 (in L atm)

+w=w*24.2;//(in cal)

+U=q+w;

+printf("q=%.2f kcal, w=%.1f cal and change in internal energy is %.4f kcal.",q/1000,w,U/1000);0

diff --git a/1427/CH18/EX18.4/18_4.sce b/1427/CH18/EX18.4/18_4.sce
new file mode 100644
index 000000000..4777a51bc
--- /dev/null
+++ b/1427/CH18/EX18.4/18_4.sce
@@ -0,0 +1,8 @@
+//ques-18.4

+//Calculating enthalpy of formation of sucrose

+clc

+h1=-393.5;//heat of combustion of carbon (in kJ/mol)

+h2=-286.2;//heat of combustion of carbon (in kJ/mol)

+h3=-5644;//heat of combustion of carbon (in kJ/mol)

+H=12*h1+11*h2-h3;//enthalpy of formation (in kJ/mol)

+printf("Enthalpy of formation of sucrose is %.1f kJ/mol.",H);

diff --git a/1427/CH18/EX18.40/18_40.sce b/1427/CH18/EX18.40/18_40.sce
new file mode 100644
index 000000000..8e3c8dbdd
--- /dev/null
+++ b/1427/CH18/EX18.40/18_40.sce
@@ -0,0 +1,10 @@
+//ques-18.40

+//Calculating final pressure and temperature on expansion of a dry gas

+clc

+T1=273;//temperature (in K)

+r=3;//ratio = V2/V1

+P1=760;//pressure (in mm Hg)

+q=1.4;

+T2=T1/(r^(q-1));

+P2=P1/(r^q);

+printf("Final pressure is %.1f atm and final temperature is %.0f K.",P2,T2);

diff --git a/1427/CH18/EX18.41/18_41.sce b/1427/CH18/EX18.41/18_41.sce
new file mode 100644
index 000000000..b259f0f25
--- /dev/null
+++ b/1427/CH18/EX18.41/18_41.sce
@@ -0,0 +1,12 @@
+//ques-18.41

+//Calculating final temperature and w and q and change in internal energy for the process

+clc

+V1=6; V2=2;//volume (in L)

+T1=273+27;//temperature (in K)

+Cv=20.91;//(in J/K/mol)

+q=1.4;

+T2=T1*((V1/V2)^(q-1));

+U=Cv*(T2-T1);

+w=-U;

+q=0;//adiabatic process

+printf("Final temperature is %.0f K, w=%.4f kJ, q=%d and change in internal energy is %.4f kJ.",T2,w/1000,q,U/1000);

diff --git a/1427/CH18/EX18.42/18_42.sce b/1427/CH18/EX18.42/18_42.sce
new file mode 100644
index 000000000..2cdb181b3
--- /dev/null
+++ b/1427/CH18/EX18.42/18_42.sce
@@ -0,0 +1,8 @@
+//ques-18.42

+//Finding value of Kp at 500 K

+clc

+G=4.833;//free energy change (in kJ/mol)

+T=500;//temperature (in K)

+//On solving, G = -2.303*R*T*log(Kp)

+Kp=0.3128;

+printf("The value of Kp is %.4f.",Kp);

diff --git a/1427/CH18/EX18.43/18_43.sce b/1427/CH18/EX18.43/18_43.sce
new file mode 100644
index 000000000..024e0254e
--- /dev/null
+++ b/1427/CH18/EX18.43/18_43.sce
@@ -0,0 +1,14 @@
+//ques-18.43

+//Calculating equilibrium constant for dissociation of acetic acid

+clc

+T=298;//temperature (in K)

+R=8.314;//(in J/mol/K)

+//G = free energy change for formation (in kJ/mol)

+G1=-396.6;//acetic acid

+G2=-369.4;//acetate ion

+G3=0;//proton

+G=G2+G3-G1;//dissociation reaction

+c=-(G*1000)/(2.303*R*T);

+//On solving, log10(K) = c;

+K=1.72*10^-5;

+printf("The equilibrium constant for the reaction is %.7f.",K);

diff --git a/1427/CH18/EX18.44/18_44.sce b/1427/CH18/EX18.44/18_44.sce
new file mode 100644
index 000000000..05412eac2
--- /dev/null
+++ b/1427/CH18/EX18.44/18_44.sce
@@ -0,0 +1,9 @@
+//ques-18.44

+//Calculating enthalpy of the reaction and free energy change and entropy change at 925 K

+clc

+T1=925; T2=1000;//temperature (in K)

+K1=18.5; K2=9.25;//equikibrium constant

+H=(log10(K2/K1)*2.303*8.314*T1*T2)/(T2-T1);//enthalpy (in J/mol)

+G=-2.303*8.314*T1*log10(K1);

+S=(H-G)/T1;

+printf("The enthalpy of the reaction is %.1f kJ/mol, free energy change is %.1f kJ/mol and entropy change is %.1f J/K/mol.",H/1000,G/1000,S);

diff --git a/1427/CH18/EX18.45/18_45.sce b/1427/CH18/EX18.45/18_45.sce
new file mode 100644
index 000000000..a8148a134
--- /dev/null
+++ b/1427/CH18/EX18.45/18_45.sce
@@ -0,0 +1,7 @@
+//ques-18.45

+//Calculating change in chemical potential of a substance

+clc

+P1=1; P2=0.5;//partial pressure (in atm)

+T=298;//temperature (in K)

+C_P=8.314*T*log(P2/P1);

+printf("The change in chemical potential is %.4f kJ/mol.",C_P/1000);

diff --git a/1427/CH18/EX18.46/18_46.sce b/1427/CH18/EX18.46/18_46.sce
new file mode 100644
index 000000000..d776715b6
--- /dev/null
+++ b/1427/CH18/EX18.46/18_46.sce
@@ -0,0 +1,8 @@
+//ques-18.46

+//Calculating decrease in chemical potential of benzene

+clc

+T=298;//temperature (in K)

+x_s=0.1;//mole-fraction of solute

+x_b=1-x_s;//mole-fraction of benzene

+C_P=8.314*T*log(x_b);

+printf("The decrease in chemical potential is %.2f J/mol.",C_P);

diff --git a/1427/CH18/EX18.5/18_5.sce b/1427/CH18/EX18.5/18_5.sce
new file mode 100644
index 000000000..876aac0a9
--- /dev/null
+++ b/1427/CH18/EX18.5/18_5.sce
@@ -0,0 +1,8 @@
+//ques-18.5

+//Calculating standard heat of formation of actylene

+clc

+h1=-1300;//heat of combustion of acetylene (in kJ)

+h2=-395;//heat of combustion of graphite(C) (in kJ)

+h3=-286;//heat of combustion of hydrogen (in kJ)

+H=2*h2+h3-h1;//heat of formation of actylene (in kJ)

+printf("Heat of formation of actylene is %d kJ/mol.",H);

diff --git a/1427/CH18/EX18.6/18_6.sce b/1427/CH18/EX18.6/18_6.sce
new file mode 100644
index 000000000..27e46ea47
--- /dev/null
+++ b/1427/CH18/EX18.6/18_6.sce
@@ -0,0 +1,8 @@
+//ques-18.6

+//Calculating standard heat of formation of n heptane

+clc

+E1=-1150;//internal energy change at constant volume (in kcal)

+h2=-94;//heat of formation of carbon dioxide (in kcal)

+h3=-68;//heat of formation of carbon dioxide (in kcal)

+H=7*h2+8*h3-E1;//heat of formation 

+printf("Heat of formation of n-heptane is %d kcal/mol.",H);

diff --git a/1427/CH18/EX18.7/18_7.sce b/1427/CH18/EX18.7/18_7.sce
new file mode 100644
index 000000000..ce22e8a00
--- /dev/null
+++ b/1427/CH18/EX18.7/18_7.sce
@@ -0,0 +1,8 @@
+//ques-18.7

+//Calculating heat of the given reaction

+clc

+h1=-26.4;//heat of formation of carbon monoxide (in kcal/mol)

+h2=-94.1;//heat of formation of carbon monoxide (in kcal/mol)

+h3=-57.8;//heat of formation of carbon monoxide (in kcal/mol)

+H=h1-h2+h3;//required heat (in kcal/mol)

+printf("Heat of the reaction is %.1f kcal/mol.",H);

diff --git a/1427/CH18/EX18.8/18_8.sce b/1427/CH18/EX18.8/18_8.sce
new file mode 100644
index 000000000..21431e5a1
--- /dev/null
+++ b/1427/CH18/EX18.8/18_8.sce
@@ -0,0 +1,9 @@
+//ques-18.8

+//Calculating heat of combustion of ethene at constant pressure

+clc

+T=17;//temperature (in degree celsius)

+E=-332.19;//heat of combustion at constant volume (in kcal)

+R=0.001987;//in kcal/K/mol

+n=2-(1+3);//difference in gaseous vapours

+H=E+n*R*(T+273);//heat of combustion at constant pressure

+printf("Heat of combustion of ethene at constant pressure is %.3f kcal/mol.",H);

diff --git a/1427/CH18/EX18.9/18_9.sce b/1427/CH18/EX18.9/18_9.sce
new file mode 100644
index 000000000..7d73421f4
--- /dev/null
+++ b/1427/CH18/EX18.9/18_9.sce
@@ -0,0 +1,11 @@
+//ques-18.9

+//Comparing theoretical efficiencies of system of engine operating at 1 and 50 atm

+clc

+T1=45;//temperature (in degree celsius)

+//Part (i)

+T2=100;//boiling temperature (in degree celsius)

+n1=(T2-T1)/(T2+273);//efficiency

+//Part (ii)

+T2=265;//boiling temperature (in degree celsius)

+n2=(T2-T1)/(T2+273);//efficiency

+printf("The two theoretical efficiencies required are %.4f and %.4f.",n1,n2);