Molecule N2o4 has a greater entropy than NO2

In summary, the statement that two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure is not false. Entropy is an extensive variable, meaning that it is dependent on the amount of substance present. Therefore, having more moles in the same conditions does not decrease the entropy. However, the statement that the entropy change for the reaction N2O4(g) -> 2 NO2(g) is positive is true. This is because N2O4 has a greater entropy than NO2, and the change in entropy would be negative (smaller - bigger number) in this reaction.
  • #1
a.a
127
0

Homework Statement



Why is this statement false?

'Two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure.'
--> Is it because the number of moles doesn't matter. Why doesn't it?

Why is this statement true?

'The entropy change for the reaction N2O4(g) -> 2 NO2(g) is positive.'
--> The molecule N2o4 has a greater entropy than NO2, so it delta S, change in entropy would be entropy of NO2 - entropy of N2O4, which would be a negative (smaller - bigger number)? Am I going about this wrong?
 
Physics news on Phys.org
  • #2


a.a said:
Why is this statement false?

'Two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure.'


It's not false; entropy is an extensive variable.
 
  • #3


If there are more moles in the same place under the same tempreature and pressure, wouldn't that decrease the entropy?
 
  • #4


Nope.
 

Related to Molecule N2o4 has a greater entropy than NO2

1. Why does molecule N2O4 have a greater entropy than NO2?

The greater entropy of N2O4 is due to its molecular structure. N2O4 has a linear structure, with two nitrogen atoms bonded together, while NO2 has a bent structure, with a nitrogen atom bonded to two oxygen atoms. This difference in structure results in more possible microstates for N2O4, leading to a higher entropy.

2. What is the relationship between molecular structure and entropy?

Molecular structure plays a significant role in determining the entropy of a molecule. Generally, molecules with more complex and diverse structures have higher entropy. This is because a greater number of possible arrangements of atoms and molecules leads to more available microstates, which is a measure of entropy.

3. Can you explain how the Second Law of Thermodynamics relates to the greater entropy of N2O4?

The Second Law of Thermodynamics states that the entropy of a closed system can never decrease over time. This means that in any physical or chemical process, the total entropy of the system and its surroundings will either increase or remain constant. In the case of N2O4 and NO2, the system with N2O4 has a higher entropy, which follows the Second Law of Thermodynamics.

4. Does the temperature of a system affect the entropy of molecules?

Yes, temperature can affect the entropy of molecules. At higher temperatures, molecules have more kinetic energy and are more likely to have greater motion and disorder, resulting in higher entropy. This is because there are more available energy levels for molecules to occupy at higher temperatures.

5. Are there any other factors besides molecular structure that can influence the entropy of a molecule?

Yes, there are other factors that can affect the entropy of a molecule, such as molecular size, molecular weight, and intermolecular forces. Generally, larger molecules have higher entropy than smaller molecules due to their greater number of atoms and microstates. Molecules with stronger intermolecular forces also tend to have lower entropy, as they are more organized and have less disorder.

Similar threads

Calculating Percentage of Dissociated N2O4 Molecules: Vapour Density Question
    • Biology and Chemistry Homework Help
Replies
1
Views
1K
Calculating Entropy Change for N2O4 Equilibrium in Constant Pressure Vessel
    • Biology and Chemistry Homework Help
Replies
4
Views
2K
What percentage of N2O4 decomposes at 370K ?
    • Biology and Chemistry Homework Help
Replies
1
Views
9K
Question on entropy in adiabatic phase change
    • Biology and Chemistry Homework Help
Replies
8
Views
2K
I Problem regarding understanding entropy
    • Thermodynamics
Replies
3
Views
794
A few physical chem questions.
    • Biology and Chemistry Homework Help
Replies
4
Views
3K
Chemistry Problem: N2O4 (g) <==> 2 NO2 (g) - Calculate Keq
    • Biology and Chemistry Homework Help
Replies
2
Views
2K
Chemistry Problem: Calculating Keq for N2O4 Gas Dissociation at 25oC
    • Biology and Chemistry Homework Help
Replies
5
Views
3K
Unknown (to me) formula of Entropy
    • Biology and Chemistry Homework Help
Replies
14
Views
1K
Calculating entropy change associated with change in temperature
    • Biology and Chemistry Homework Help
Replies
6
Views
3K

Hot Threads

Recent Insights

Back
Top