Final answer:
The processes that can take place at 298K without violating the second law of thermodynamics are: spontaneous expansion of a gas into a vacuum and conversion of heat completely into work with 100% efficiency.
Step-by-step explanation:
The processes that can take place at 298K without violating the second law of thermodynamics are:
- Spontaneous expansion of a gas into a vacuum: When a burst of gas is released into a vacuum chamber, it quickly expands to uniformly fill every part of the chamber. The random motions of the gas molecules prevent them from returning to their original position, making this process irreversible.
- Conversion of heat completely into work with 100% efficiency: According to the second law of thermodynamics, it is impossible for a system to convert heat transfer completely into work in a cyclical process where the system returns to its initial state. However, in an idealized, theoretical scenario, a reversible process could achieve 100% efficiency.
The processes that can take place at 298K without violating the second law of thermodynamics include spontaneous expansion of a gas into a vacuum. This complies with the natural tendency of systems to progress towards a state of greater entropy.
The second law dictates that heat transfer can only occur spontaneously from a hot object to a cold one, and not the reverse, meaning heat cannot spontaneously transfer from a colder body to a hotter body. Additionally, the complete conversion of heat into work with 100% efficiency is not possible for any real machine.
This law also discredits the existence of a perpetual motion machine of the first kind, as it would violate the principles of energy conservation and entropy.