Why Does Heat Come from the Air to Melt Ice in Water?

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SUMMARY

Heat transfer in the scenario of melting an ice cube in water at 0 degrees Celsius occurs primarily from the air rather than the water. This is due to the requirement of a temperature difference for heat flow; without heat from the air, the water and ice would equilibrate at 0 degrees Celsius, halting any melting process. The total entropy change of the universe is calculated using the formula ΔSuniverse = ΔSice + ΔSwater + ΔSair, indicating that all components must be considered in thermodynamic calculations.

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  • Understanding of thermodynamics principles, specifically heat transfer.
  • Knowledge of entropy and its calculation in thermodynamic systems.
  • Familiarity with the concept of temperature equilibrium.
  • Basic grasp of the laws of thermodynamics.
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  • Study the principles of heat transfer, focusing on conduction, convection, and radiation.
  • Research the laws of thermodynamics, particularly the first and second laws.
  • Explore detailed examples of entropy calculations in various thermodynamic processes.
  • Learn about temperature gradients and their role in heat flow dynamics.
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Chronos000
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Homework Statement



an ice cube is melted in water which is continuously stirred to be at a constant temperature of 0 degrees. the stirring is gentle enough so the work done is negligible.

my question is why in this case does the heat come from the air to melt the ice cube and not the water. why can't it be a bit of both or just the water.

also, for the total entropy change of the universe, wouldn't I just consider the S:ice + S:water = S:air?
 
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Chronos000 said:

Homework Statement



an ice cube is melted in water which is continuously stirred to be at a constant temperature of 0 degrees. the stirring is gentle enough so the work done is negligible.

my question is why in this case does the heat come from the air to melt the ice cube and not the water. why can't it be a bit of both or just the water.
Heat flow requires a temperature difference. Without heat flowing from the air to the water/ice, the water and the ice would reach and remain at the same temperature, 0C, and then there would be no further heat flow. So heat flow must occur from the surroundings to the water/ice.
also, for the total entropy change of the universe, wouldn't I just consider the S:ice + S:water = S:air?
The total entropy change is:

\Delta S_{universe} = \Delta S_{ice} + \Delta S_{water} + \Delta S_{air}

AM
 

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