✅3.7 Entropy and Feasibility Of Reactions Flashcards
What is entropy
Entropy is described as the value of disorder in a system
Chemists view entropy as the degree of freedom of a system, particles that can move freely in any direction have a much higher entropy than particles that are constrained
Give an example of a system when entropy is low
A system where atoms are in fixed positions, without any freedom to move, typical of a solid
Give an example of a system with a medium entropy
A system where atoms are free to move in any direction but must stay close together, then the entropy is greater than those atoms fixed in a system, this is typical of a liquid
Describe a system when entropy would be High
If atoms in a system are free to move in any direction and move to any position then entropy is highest, this is typical of a gas.
Give the way of describing entropy in all three physical states
Entropy: S(solid) < S(liquid) < S(gas)
What is entropy represented by?
What is it measured in?
What is standard entropy measured in?
Entropy is represented by a capital S (S)
Entropy is measured in J K-1
Standard entropy is measured in J K-1 mol-1
What is the standard entropy of a substance?
The entropy of one mole of a substance in a given physical state under standard conditions.
What is the change in entropy equation?
🔺S = S(all products)-S(all reactants)
What does the second law of thermodynamics state?
Entropy will always tend to increase in any is listed system that is not in equilibrium.
This means that if you take any ordered system that is not in equilibrium it will tend to increase its overall degree of freedom unless work is done to it.
What is the Gibbs free energy equation?
🔺G = 🔺H -🔺T
When 🔺G= the change in the Gibbs free energy, in KJ/J mol-1
When 🔺S= the entropy change in KJ/J mol -1
When 🔺T= temperature in Kelvin (K)
