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💏intro to chemistry review

key term - $ ext{Delta S}_{ ext{universe}}$

Citation:

Definition

$ ext{Delta S}_{ ext{universe}}$ refers to the change in entropy of the entire universe during a spontaneous process. Entropy is a measure of the disorder or randomness of a system, and the second law of thermodynamics states that the entropy of the universe always increases for a spontaneous process.

5 Must Know Facts For Your Next Test

  1. The change in entropy of the universe, $ ext{Delta S}_{ ext{universe}}$, is always greater than or equal to zero for a spontaneous process.
  2. A spontaneous process is a process that occurs naturally without the input of external energy and leads to an increase in the entropy of the universe.
  3. The second law of thermodynamics states that the entropy of the universe always increases for a spontaneous process.
  4. The change in entropy of the universe is the sum of the change in entropy of the system and the change in entropy of the surroundings.
  5. The spontaneity of a process is determined by the sign of $ ext{Delta S}_{ ext{universe}}$, where a positive value indicates a spontaneous process and a negative value indicates a non-spontaneous process.

Review Questions

  • Explain the relationship between $ ext{Delta S}_{ ext{universe}}$ and the spontaneity of a process.
    • The change in entropy of the universe, $ ext{Delta S}_{ ext{universe}}$, is directly related to the spontaneity of a process. According to the second law of thermodynamics, for a spontaneous process, $ ext{Delta S}_{ ext{universe}}$ is always greater than or equal to zero. A positive value of $ ext{Delta S}_{ ext{universe}}$ indicates that the process is spontaneous and will occur naturally, while a negative value of $ ext{Delta S}_{ ext{universe}}$ indicates a non-spontaneous process that requires the input of external energy to occur.
  • Describe how the change in entropy of the system and the surroundings contribute to $ ext{Delta S}_{ ext{universe}}$.
    • The change in entropy of the universe, $ ext{Delta S}_{ ext{universe}}$, is the sum of the change in entropy of the system, $ ext{Delta S}_{ ext{system}}$, and the change in entropy of the surroundings, $ ext{Delta S}_{ ext{surroundings}}$. For a spontaneous process, $ ext{Delta S}_{ ext{system}}$ is typically positive, indicating an increase in disorder within the system. The change in entropy of the surroundings, $ ext{Delta S}_{ ext{surroundings}}$, is also typically positive, as the surroundings must absorb or release energy to maintain a constant temperature. The sum of these two changes, $ ext{Delta S}_{ ext{universe}} = ext{Delta S}_{ ext{system}} + ext{Delta S}_{ ext{surroundings}}$, is always greater than or equal to zero for a spontaneous process.
  • Analyze how the sign of $ ext{Delta S}_{ ext{universe}}$ can be used to predict the spontaneity of a chemical reaction.
    • The sign of $ ext{Delta S}_{ ext{universe}}$ can be used to predict the spontaneity of a chemical reaction. If $ ext{Delta S}_{ ext{universe}}$ is positive, the reaction is spontaneous and will occur naturally. If $ ext{Delta S}_{ ext{universe}}$ is negative, the reaction is non-spontaneous and will not occur naturally without the input of external energy. By calculating the change in entropy of the system and the surroundings, and then determining the overall change in entropy of the universe, $ ext{Delta S}_{ ext{universe}}$, one can assess the spontaneity of a chemical reaction. This understanding is crucial for predicting the feasibility and direction of chemical processes.