Answer: The change in entropy of the lead when 2.0 kg of molten lead at its melting point temperature solidifies is 20 cal/K.
Explanation:
[tex]Pb(l)\rightleftharpoons Pb(s)[/tex]
[tex]\Delta S=\frac{q}{T}[/tex]
[tex]{\text{Change in entropy}}=\frac{heat}{Temperature}[/tex]
T is the temperature at which the process is carried out, here the temperature is constant, 327.5°C = [tex](273+327.5)K=600.5K[/tex] ,because only phase change occurs.
q = heat given in the process = [tex]m\times L_f[/tex]
m = mass of lead = 2.0 kg
[tex]L_f[/tex] = latent heat of fusion of lead = 5.9 kcal/kg
[tex]\Delta S=\frac{2kg\times 5.9kcal/kg}{600.5K}[/tex]
[tex]\Delta S=0.02 kcal/K=20cal/K[/tex]
Thus the change in entropy of the lead when 2.0 kg of molten lead at its melting point temperature solidifies is 20 cal/K.
