Van't Hoff Approach to Finding ∆H and ∆S

  • Thread starter Thread starter ampakine
  • Start date Start date
  • Tags Tags
    Approach
Click For Summary
SUMMARY

The discussion centers on the application of the Van't Hoff equation to determine the standard enthalpy change (∆H) and entropy change (∆S) for a reaction. The equation incorporates ∆Ho, which represents the enthalpy change for one mole of reactant at 298K. It is clarified that T1 does not always have to be 298K; however, to calculate ∆Ho, one must input 298K for T1 and the corresponding equilibrium constant (K) for that temperature. The assumption that ∆H remains constant with temperature is noted as a limitation of this approach.

PREREQUISITES
  • Understanding of the Van't Hoff equation
  • Knowledge of thermodynamic concepts such as enthalpy (∆H) and entropy (∆S)
  • Familiarity with the concept of equilibrium constants (K)
  • Basic calculus for integration and differentiation
NEXT STEPS
  • Study the derivation of the Van't Hoff equation in detail
  • Learn about the relationship between temperature and equilibrium constants
  • Explore the concept of standard enthalpy changes in thermodynamics
  • Investigate the limitations of assuming constant ∆H with temperature changes
USEFUL FOR

Chemistry students, researchers in thermodynamics, and professionals involved in chemical kinetics and equilibrium studies will benefit from this discussion.

ampakine
Messages
60
Reaction score
0
Heres the question:
[PLAIN]http://img194.imageshack.us/img194/9042/vanthoff.png
and here's the Van't Hoff equation (the form I like to use):
[PLAIN]http://img703.imageshack.us/img703/1577/vtequation.png
I'm a bit confused about what's going on here. I see the formula includes ∆Ho, meaning the enthalpy change for 1 mole of reactant at 298K. Does that mean to use this formula T1 always has to be 298K? In other words to get the ∆Ho for the reaction would I just plug 298K into T1 and 4.25 x 10-7 into KT1 then plug any other pair of values from that table into T2 and KT2?
 
Last edited by a moderator:
Chemistry news on Phys.org
The ∆H is always assumed to be constant with temp in this equation (standard enthalpy change), which is an obvious downside to the relation. If you derive it from
(d ln(K)) / (d 1/T) = -∆Ho/R you will find that from the integration.
 

Thread 'Gold hydride - what is the significance?'

I came.across a headline and read some of the article, so I was curious. Scientists discover that gold is a 'reactive metal' by accidentally creating a new material in the lab https://www.earth.com/news/discovery-that-gold-is-reactive-metal-by-creating-gold-hydride-in-lab-experiment/ From SLAC - A SLAC team unexpectedly formed gold hydride in an experiment that could pave the way for studying materials under extreme conditions like those found inside certain planets and stars undergoing...
View full post »

Similar threads

How Is Tension Calculated in an Atwood's Machine?
  • · Replies 1 ·
Replies
1
Views
10K
Simple Pulley Ratios: Find T1, T2, T3, T4, T5, F
  • · Replies 15 ·
Replies
15
Views
14K
Plug in time to find the acceleration
  • · Replies 3 ·
Replies
3
Views
2K
Are My Physics Solutions Correct?
  • · Replies 3 ·
Replies
3
Views
2K
Detecting matter falling into a Black Hole
  • · Replies 85 ·
3
Replies
85
Views
8K
Projectile Motion in 3rd, finding out where 2 paths cross
  • · Replies 2 ·
Replies
2
Views
5K
Solving the Dispute: Criticism of Hartle-Hawking Model Explained
  • · Replies 5 ·
Replies
5
Views
7K
Exhaust and engine accoustics for asthetics and performance
  • · Replies 2 ·
Replies
2
Views
8K
Mathematica This Week's Finds in Mathematical Physics (Week 239)
  • · Replies 1 ·
Replies
1
Views
3K
Mathematica This Week's Finds in Mathematical Physics (Week 259)
  • · Replies 1 ·
Replies
1
Views
3K