What Does Svante Arrhenius' Salt Water Experiment Reveal About Entropy?

Click For Summary
SUMMARY

The discussion centers on Svante Arrhenius' salt water experiment, which illustrates the relationship between electrical charge and entropy in a solution of salt water. Participants explore how ions, specifically Cl- and K+, arrange themselves when an electrical charge is applied, leading to a perceived increase in order. This arrangement suggests a decrease in entropy, although it is clarified that energy is being subtracted from the system as mechanical energy is converted to electrical energy. The conversation emphasizes the need for relevant equations to quantify entropy changes in this context.

PREREQUISITES
  • Understanding of entropy and its implications in thermodynamics
  • Familiarity with Svante Arrhenius' contributions to physical chemistry
  • Knowledge of Boltzmann's statistical mechanics
  • Basic principles of electrical charge interactions in ionic solutions
NEXT STEPS
  • Research the entropy variation equation for ionic solutions under electrical fields
  • Study Boltzmann's entropy formula and its applications in statistical physics
  • Examine the thermodynamic principles governing energy transfer in ionic systems
  • Explore experimental setups similar to Arrhenius' to observe entropy changes
USEFUL FOR

This discussion is beneficial for physicists, chemistry students, and anyone interested in the thermodynamic properties of ionic solutions and the effects of electrical fields on entropy.

Bernadette
Messages
29
Reaction score
0
Hello

Sorry for my English...

We approach slowly (in a quasi-reversible way) an electrical charge of a glass of salt water.
Some ions arrange themselves in the glass.

What can we say about entropy of this transformation?

Bernadette

PS: My reflection comes from reading an old physics book (in French...) where an experiment by Svante Aarhenius, the "father" of ions, is described.

IMG_2001.jpg
 
Science news on Phys.org
Welcome to PF. :smile:

In the schoolwork forums and the technical forums, we require that you tell us what you think will happen. Can you show us the relevant equations that decsribe the Entropy of this setup, and tell us what you think will happen to the value of the Entropy? Thanks.
 
Hello

As it is showed on the picture, some ions (Cl- and K+) move.
In the sense of Boltmann's statistical physics, we have more order after approaching the charge.
I don't know the entropy variation equation for this transformation, if it exists.
I want to write that entropy decreases but I know it's impossible.

Bernadette
 
Bernadette said:
I want to write that entropy decreases but I know it's impossible.
But is energy being added or subtracted from this system? :wink:

Also, is this for schoolwork? I can move your thread to the schoolwork forums if that is a better match...
 
Hello

We receive mechanical energy as electrical charges approach. So energy is subtracted from this (isolated) system.
It is not a schoolwork. Just asking questions in my mind. I am no more student, (regrets)

From the other side of Atlantic ocean.

Bernadette
 
Hello

No more response?

Can we say that when we apply the electric field (we approach the charge), the order increases?

Have a nice day

Bernadette
 

Similar threads

Undergrad Oil and Water Experiment Question
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad What does Purcell actually say about electromagnetism and relativity?
  • · Replies 32 ·
2
Replies
32
Views
7K
Schools Remarks on AP courses in high school
  • · Replies 110 ·
4
Replies
110
Views
24K
What Are the Evolutionary and Developmental Functions of Dreams?
  • · Replies 6 ·
Replies
6
Views
10K
Can You Stomach These Extreme Global Delicacies?
  • · Replies 78 ·
3
Replies
78
Views
13K