Calculate the change in entropy when 1.00 kg of water at 100 degree C is vaporized and converted to steam at 100 degree C. Assume that the heat of vaporization of water is 2256 Times 103 J/kg. Calculate the change in entropy when 1.00 kg of ice is melted at 0 degree C. Assume that the heat of fusion of water is Lf = 3.34 Times 105J/kg. Is the change entropy greater for melting or for vaporization? the change entropy greater for melting the change entropy greater for vaporization

Respuesta :

Answer:

Case 1 : Entropy of vaporization of water is [tex]\Delta S=6.048 \times 10^{3}[/tex]

Case 2 :Entropy of fusion of ice is [tex]\Delta S=1.2234 \times 10^{3}[/tex]

Result : Entropy of vaporization of water is greater than entropy of fusion of ice

Explanation:

Entropy of closed system is given by [tex]\Delta S=\frac{\Delta Q}{T}[/tex]

Where [tex]\Delta S [/tex] is change of entropy, [tex]\Delta Q [/tex] is change of heat and T is absolute temperature in kelvin

Case 1 : During vaporization of water

It is said that " 1.00 kg of water at 100 degree C is vaporized and converted to steam at 100 degree C"

Given Heat of vaporization of water is [tex]2256 \times 10^{3}[/tex] J/kg.

[tex]\Delta Q = mL[/tex]

m=1 kg of water

L=[tex]2256 \times 10^{3}[/tex] J/kg.

[tex]\Delta Q = mL = 2256 \times 10^{3}[/tex]

Entropy of closed system is given by [tex]\Delta S=\frac{\Delta Q}{T}[/tex]

Where, T=100+273=373K

[tex]\Delta S=\frac{ 2256 \times 10^{3}}{373}[/tex]

[tex]\Delta S=6.048 \times 10^{3}[/tex]

Thus, Entropy of vaporization of water is [tex]\Delta S=6.048 \times 10^{3}[/tex]

Case 2 : During fusion of ice

It is said that " 1.00 kg of ice at 0 degree C is melted and converted to water at 0 degree C"

Given Heat of fusion of ice is [tex]3.34 \times 10^{5}[/tex] J/kg.

[tex]\Delta Q = mL[/tex]

m=1 kg of ice

L=[tex]3.34 \times 10^{5}=334 \times 10^{3} J/kg.

[tex]\Delta Q = mL = 334 \times 10^{3}[/tex]

Entropy of closed system is given by [tex]\Delta S=\frac{\Delta Q}{T}[/tex]

Where, T=0+273=273K

[tex]\Delta S=\frac{ 334 \times 10^{3}}{373}[/tex]

[tex]\Delta S=1.2234\times 10^{3}[/tex]

Thus, Entropy of fusion of ice is [tex]\Delta S=1.2234 \times 10^{3}[/tex]

Therefore, Entropy of vaporization of water is greater than entropy of fusion of ice