If a supersaturated sugar solution is allowed to evaporate slowly, sugar crystals form in the container. Hence, sugar molecules go from a disordered form (in solution) to a highly ordered, crystalline form. Does this process violate the second law of thermodynamics? Explain.
No, this process does not violate the second law of thermodynamics. The second law states that the entropy (disorder) of an isolated system will either remain constant or increase over time. In this case, the formation of sugar crystals corresponds to a decrease in the entropy of the sugar molecules as they go from a disorderly arrangement in solution to an orderly arrangement as crystals.
However, this process does not involve an isolated system. The solution, which contains sugar molecules, is in contact with its surroundings, such as air. When water evaporates from the solution, heat is transferred from the solution to the environment. This evaporation and heat transfer to the surroundings results in an increase of entropy in the environment.
When considering the total entropy change of both the solution and the environment, it is seen that the increase in entropy due to heat transfer to the environment is much larger than the decrease in entropy due to the ordering of sugar molecules into crystals. Consequently, the overall entropy of the combined system (solution and environment) increases, satisfying the second law of thermodynamics. Thus, the process does not violate the second law.
The second law of thermodynamics states that the entropy of an isolated system tends to increase over time. Entropy can be thought of as a measure of the disorder or randomness within a system. Based on this understanding, it might seem like the process of sugar molecules going from a disordered form in solution to a highly ordered, crystalline form would violate the second law. However, this is not the case.
To explain why this process does not violate the second law of thermodynamics, we need to consider the entire system, not just the sugar solution. When a supersaturated sugar solution is allowed to evaporate slowly, the surrounding environment plays a crucial role.
As the solvent (water) evaporates from the solution, the concentration of sugar becomes higher, eventually reaching a point where the sugar molecules can no longer stay dissolved and start to come together to form crystals. This process is driven by the decrease in free energy associated with the formation of stable sugar crystals.
Although the sugar molecules become more ordered in the crystalline form, there is an increase in the entropy of the overall system. This increase in entropy occurs because the surrounding environment, including the water molecules that evaporate, becomes more disordered. The net effect is that the total entropy of the system, including the sugar crystals and the surroundings, still increases as required by the second law of thermodynamics.
So, even though the sugar molecules transition from a disordered to a highly ordered arrangement, the overall system's entropy increases, ensuring that the second law of thermodynamics is not violated.
No, the process of sugar molecules going from a disordered form in a supersaturated solution to a highly ordered, crystalline form does not violate the second law of thermodynamics. The second law states that the entropy of an isolated system tends to increase over time, and in this case, the overall entropy of the system does increase.
During the evaporation process, the water molecules in the solution are slowly removed, which reduces the disorder in the system. The organization of sugar molecules into a crystalline structure also results in a decrease in the system's entropy. However, the combination of these changes is offset by the increase in entropy that occurs in the surroundings.
As the water evaporates, it carries away heat, which increases the entropy of the surroundings. The overall change in entropy, considering both the decrease in entropy within the system and the increase in entropy in the surroundings, is positive. Therefore, this process does not violate the second law of thermodynamics.