Determining Delta S of Cl2 + Br2 --> 2BrCl

  • Thread starter Thread starter qwexor
  • Start date Start date
  • Tags Tags
    Delta
Click For Summary

Discussion Overview

The discussion revolves around determining the change in entropy (Delta S) for the reaction Cl2(g) + Br2(g) <--> 2BrCl(g). Participants explore how to assess whether Delta S is positive or negative, considering theoretical and practical approaches to entropy calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests looking up the entropy values for each substance to calculate the change in entropy.
  • Another participant argues that the left side has higher entropy due to more possible arrangements of molecules compared to the single compound on the right side, leading to the conclusion that Delta S is negative.
  • A different participant emphasizes the simplicity of the comparison by counting the number of different molecules on each side, asserting that the decrease in the number of molecules indicates a decrease in entropy.
  • One participant introduces the idea that excluding Delta S_{mixing} might be necessary, as it could have a significant effect on the overall entropy change.
  • Another participant notes that the molar ratio of products to reactants is the same and suggests that further investigation into standard entropy values may be needed.

Areas of Agreement / Disagreement

Participants express differing views on how to approach the determination of Delta S, with some focusing on molecular counts while others suggest looking up standard values. No consensus is reached regarding the final assessment of Delta S.

Contextual Notes

Some participants mention the potential influence of Delta S_{mixing} and the need for standard entropy values, indicating that assumptions about the reaction conditions and definitions of entropy may affect the discussion.

qwexor
Messages
7
Reaction score
0
Hello Everyone,

I'm reviewing for my chem 12 midterm and just came across a question that I'm not sure about. If I have the following Reaction:


Cl2(g) + Br2(g) <---> 2BrCl (g)

How can i determine whether the change in entropy (Delta S), is positive or negative.

Thanks!,
Nick
 
Chemistry news on Phys.org
you can look up the entropy values for each substance and then find the difference between the two sides to find the change in entropy.
 
qwexor said:
Cl2(g) + Br2(g) <---> 2BrCl (g)

How can i determine whether the change in entropy (Delta S), is positive or negative.
Well which side will have the higher entropy? That is the first question.

I think:The left side will have a higher entropy than the right side because there are more possible arrangments for the molecules on the left hand side than there are on the right hand side (as this is just one compound).

I, therefore, think it is negative because the entropy has decreased.[/color] (in white so that qwexor has the option of looking or not).

The Bob (2004 ©)
 
Your are thinking way too hard. Do like bob said. How many different molecules do you have on the left side of the equation? How many different molecules are on the right side of the equation. 2 on the left and 1 on the right, therefore entropy has decreased. See how easy that was? Don't let your education interfere with your intelligence.
 
The above solutions work best if you exclude [itex]\Delta S _{mixing}[/itex] which may be of the same order, though opposite sign as [itex]\Delta S _{reaction}[/itex].
 
There seems to be two molecules for two molecules, as the right has the coefficient of 2. The molar ratio of products to ratio is the same. For this problem you might need to browse through the standard entropy values. It might be the case that the reactant side, entropy is zero. I'll have to read up more.
 
Last edited:

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 1 ·
Replies
1
Views
8K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 18 ·
Replies
18
Views
24K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 1 ·
Replies
1
Views
13K
  • · Replies 2 ·
Replies
2
Views
9K