A beverage company advertises a "self-chilling can." The sealed can is said to draw thermal energy from the beverage (initially at 295K) and reject it to the surrounding air (also at 295K) so that the drink rapidly cools to 280K without any external power source or change in the can’s mass.
Assume the beverage, the can walls, and the surrounding air are the only objects involved in the process. No chemical or nuclear reactions occur, and mechanical motion is negligible.
(a) Define a convenient system boundary that allows you to analyze whether the advertised process violates the second law of thermodynamics. Justify your choice.
(b) Qualitatively describe the entropy change of each of the following during the cooling process:
• the beverage,
• the surrounding air,
• the can walls.
State whether each change is positive, negative, or approximately zero and explain your reasoning.
(c) Based on your analysis in part (b), predict the sign (positive, negative, or zero) of the total entropy change for the system plus surroundings. Explain how this prediction determines whether the company’s claim can be correct.