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+//ques9
+//Entropy Change of an Ideal Gas
+clear
+clc
+//(a) From table (Table A–17)
+s2=1.79783;//entropy of substance a state 2 in kJ/Kg.K  
+s1=1.66802;//entropy of state 2 in kJ/kg.k
+R=0.287;//gas constant for water
+P2=600//final pressure in kPa
+P1=100//initial pressure in kPa
+dS=s2-s1-R*log(P2/P1);//change in entropy in kJ/kg.k
+printf('(a) s2-s1 = %.4f kJ/Kg.K \n',dS);
+
+//(b) by using a c value at the average temperature 37 C 
+Cpavg=1.006//avg specific heat at const pressure in kJ/kg.K
+T2=330//final temp in K
+T1=290//inial temp in K
+dS=Cpavg*log(T2/T1)-R*log(P2/P1);//kJ/kg.k
+printf(' (b) Entropy change = %.4f kJ/kg.K',dS);
+