In a vacuum bottle, 320 g of water and 120 g of ice are initially in equilibrium at 0.00∘∘C. The bottle is not a perfect insulator. Over time, its contents come to thermal equilibrium with the outside air at 25.0∘∘C. 1) How much does the entropy of universe increase in the process?

Respuesta :

Answer:

Δ[tex]S_{univ}=267.7J/K[/tex]

Explanation:

Hello,

To find the change in the entropy of the universe, we must take into account the following entropy balance:

Δ[tex]S_{univ}=\frac{Q_{water}+Q_{ice}}{T_{univ}}[/tex]

We can stand the universe as the surroundings so the [tex]T_{univ}[/tex] equals the outside air temperature. Then, we must compute both the water's and ice's released heat due to their interaction with the "hot" air:

[tex]Q_{water}=320g*4.18J/g^0C*(25-0)^0C= 33440J[/tex]

[tex]Q_{ice}=m_{ice}*(H_{melt,ice}+Cp_{ice}*(T_{univ}-T_{initial}))\\Q_{ice}=120g*(333.7J/g+2.11J/g^0C*(25-0)^0C)\\Q_{ice}=46374J[/tex]

Finally, we obtain the change (increasing) in the entropy of the universe as follows:

Δ[tex]S_{univ}=\frac{33440J+46374J}{(25+273.15)K}[/tex]

Δ[tex]S_{univ}=267.7J/K[/tex]

* All the data were extracted from Cengel's thermodynamics book.

Best regards.