Why is the following situation impossible? Two samples of...

Why is the following situation impossible? Two samples of water are mixed at constant pressure inside an insulated container: $1.00 \mathrm{kg}$ of water at $10.0^{\circ} \mathrm{C}$ and $1.00 \mathrm{kg}$ of water at $30.0^{\circ} \mathrm{C} .$ Because the container is insulated, there is no exchange of energy by heat between the water and the environment. Furthermore, the amount of energy that leaves the warm water by heat is equal to the amount that enters the cool water by heat. Therefore, the entropy change of the Universe is zero for this process.

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Second Law of Thermodynamics

This principle states that the entropy of an isolated system can never decrease over time and for any real, spontaneous process, entropy must increase. Even if energy is conserved and there is no heat exchange with the surroundings, any irreversible process, like mixing water at different temperatures, will generate additional entropy.

Irreversible Processes

Irreversible processes are those that do not occur in a reversible, quasi-static manner and always result in the production of entropy. When two substances at different temperatures mix, the internal redistribution of energy is intrinsically irreversible, leading to an increase in entropy, which contradicts the notion of a zero net entropy change.

Entropy Generation

In any actual (irreversible) process, there is an intrinsic production of entropy due to factors such as finite temperature differences during heat transfer. This internal generation of entropy implies that even if no net heat is exchanged with the environment in an insulated system, the mixing process itself will still result in a net increase in the system's total entropy.

Please give Ace some feedback