Chemistry - Entropy Changes in Physical Processes

Click For Summary
SUMMARY

The discussion focuses on the changes in entropy during various physical processes, specifically purification, mixing, freezing, evaporation, and separation. The consensus is that purification, mixing, and freezing result in a decrease in entropy, while evaporation and separation lead to an increase in entropy. The key principle is that entropy increases when a system transitions from a state of lower disorder to higher disorder, and decreases when moving from higher disorder to lower disorder. The initial interpretations of the processes were incorrect, highlighting the need for clarity in defining "substance" in the context of mixing.

PREREQUISITES
  • Understanding of the second law of thermodynamics
  • Familiarity with the concept of entropy in physical chemistry
  • Knowledge of physical processes such as freezing and evaporation
  • Basic grasp of disorder and its relation to entropy changes
NEXT STEPS
  • Study the second law of thermodynamics in detail
  • Explore the concept of entropy in chemical reactions
  • Research the role of temperature in entropy changes
  • Examine case studies of entropy changes in various physical processes
USEFUL FOR

Chemistry students, educators, and anyone interested in understanding the principles of entropy and its application in physical processes.

ncm2
Messages
14
Reaction score
0

Homework Statement


Indicate how entropy of the system changes for each of the physical processes shown below.
Entropy increases, entropy decreases, entropy does not change.

1. Purification
2. Mixing
3. Freezing
4. Evaporation
5. Separation


Homework Equations



Entropy increases when it goes from less to more disorder.
Entropy decreases when it goes from more to less disorder.

The Attempt at a Solution



Purification - many to one substance, so entropy decreases
Mixing - many to one substance, so entropy decreases
Freezing - more to less disorder, so entropy decreases
Evaporation - less to more disorder, so entropy increases
Separation - one to many substances, so entropy increases

These are wrong, but I can't think of why. Help is much appreciated.
 
Physics news on Phys.org
Mixing - many to one substance... Do you mean that solution is ONE SUBSTANCE? What do you mean by one substance?
 

Similar threads

Chemistry How to reason about Gibbs energy change due to entropy not enthalpy?
  • · Replies 4 ·
Replies
4
Views
2K
Chemistry No heat exchange with the surroundings in an irreversible expansion of an ideal gas?
  • · Replies 4 ·
Replies
4
Views
2K
Chemistry For irreversible process from state 1 to 2, why can the system not be isolated for reversible process from 1 to 2?
  • · Replies 2 ·
Replies
2
Views
2K
Chemistry How does it work to mix two gases reversibly in this device?
  • · Replies 1 ·
Replies
1
Views
2K
Chemistry Entropy in isolated composite system for irreversible process
  • · Replies 3 ·
Replies
3
Views
2K
Chemistry Two approaches to calculating entropy differ by factor of two. Why?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How would the laws of thermodynamics change in a contracting universe?
  • · Replies 5 ·
Replies
5
Views
2K
Chemistry A calculation of enthalpy, entropy, and Gibbs energy of vaporization
  • · Replies 1 ·
Replies
1
Views
2K
Question on entropy in adiabatic phase change
  • · Replies 8 ·
Replies
8
Views
3K
Could the Laws of Physics Be Proportional to Entropy?
  • · Replies 5 ·
Replies
5
Views
590