Chapter 4 : Heat changes and heat capacities

Example 4.1 Page No : 54

In [2]:
# Variables
T1 = 400.    			#K
T2 = 300. 	    		#K
k1 = 6.095 		    	#cal mole**-1 K**-1
k2 = 3.253*10**-3 			#cal mole**-1 K**-2
k3 = -1.017*10**-6 			#cal mole**-1 K**-3

# Calculations
dH = k1*(T1-T2)+0.5*k2*(T1**2-T2**2)+(1./3)*k3*(T1**3-T2**3)

# Results
print  'Heat required to raise the temperature  = %d cal-mole**-1'%(dH)

Heat required to raise the temperature  = 710 cal-mole**-1

Example 4.2 Page No : 56

In [2]:
# Variables
p1 = 10. 			#atm
p2 = 1. 			#atm
T1 = 25. 			#C
n = 2/5.

# Calculations
T2 = (p1/p2)**n*(273+T1)-273

# Results
print  'Final temperature  = %.f C'%(T2)

Final temperature  = 476 C

Example 4.3 Page No : 57

In [3]:
# Variables
p1 = 20. 			#atm
p2 = 200. 			#atm
T1 = 25. 			#C
n = 2/7.

# Calculations
T2 = (p1/p2)**n*(273+T1)-273

# Results
print  'Final temperature  = %.f C'%(T2)

Final temperature  = -119 C

Example 4.4 Page No : 58

In [4]:
# Variables
Cv = 5*4.18*10**7 			#ergs deg**-1 mole**-1
T1 = 25. 			#C
P2 = 5. 			#atm
P1 = 1. 			#atm
n = 2./7

# Calculations
W = Cv*(273+T1)*(1-(P2/P1)**n)

# Results
print  'Work of expansion  = %.2e ergs mole**-1'%(W)

Work of expansion  = -3.64e+10 ergs mole**-1

Example 4.5 Page No : 64

In [5]:
# Variables
Ti = 25. 			#C
p = 200. 			#atm
p = 1.   			#atm
dT = 31 			#C 

# Calculations
Tf = Ti-dT

# Results
print  'Final temperature  = %.f degrees'%(Tf)

Final temperature  = -6 degrees

Example 4.6 Page No : 65

In [6]:
# Variables
k1 = 6.45       			#cal deg**-1 mol**-1
k2 = 1.41*10**-3 			#cal deg**-2 mol**-1
k3 = -0.81*10**-7 			#cal deg**-3 mol**-1
T = 300 		        	#K
k4 = -0.21*1.36 			#cal deg**-3 mol**-1 atm**-1
k5 = 6.87*1.5			    #cal deg**-3 mol**-1 atm**-2
p = 10**-3

# Calculations
Cp = k1+k2*T+k3*T**2
dCp = k2+2*k3*T
dCp1 = k4*p+k5*p

# Results
print  'Cp  = %.2f cal deg**-1 mole**-1'%(Cp)
print  ' Specific heat at temperature  = %.2e cal deg**-2 mole**-1'%(dCp)
print  ' Specific heat at pressure  = %.2e cal deg**-2 mole**-1 atm**-1'%(dCp1)

Cp  = 6.87 cal deg**-1 mole**-1
 Specific heat at temperature  = 1.36e-03 cal deg**-2 mole**-1
 Specific heat at pressure  = 1.00e-02 cal deg**-2 mole**-1 atm**-1
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