Entropy in the Universe Flashcards
What composes the System
Reactants and products in a chemical reaction
What composes the Surroundings
Everything else that is not the chemical reaction
What composes the Universe
The system and the surroundings
How does enthalpy change during an endothermic reaction for the surroundings
negative (heat is given to the system from the surroundings)
How does enthalpy change during an exothermic reaction for the surroundings
positive (heat is released from a reaction INTO the surroundings)
How does enthalpy change during and endothermic reaction for the system
positive (heat is given from the surroundings and put into the system)
How does enthalpy change during an exothermic reaction for the system
negative (heat is given off/lost by the system during reaction)
What is the stated in the Second Law of Thermodynamics
For a process to be spontaneous S(univ) must be positive. (A system may under go a decrease in entropy if the surroundings undergo a larger increase in entropy and vice versa)
if S(univ) is zero what does this imply
That the system is at equilibrium
If S(univ) is negative, is the process spontaneous
No, S(univ) must be positive for a process to be spontaneous
Does Thermodynamics tell us the rate at which spontaneity will occur?
No, only if it WILL occur
What is state in the Third Law of Thermodynamics
The entropy of a perfect crystalline substance is zero at absolute zero.
What does S(univ) help us do
Predict spontaneity. Positive if spontaneous
