What is Ellingham diagram?Explain briefly.
Asked by Suvida Sobhanan
11th October 2012,
7:25 PM
Answered by Expert
Answer:
An Ellingham diagram is a graph showing the temperature dependence of the stability for compounds.
Ellingham plotted the experimentally determined standard free energy of
formation, ?G 0 , of various oxides using one mole of oxygen with temperature.
(2x/y) M(s) + O 2 (g) ------> (2/y) M x O y (s) ; ?G 0 =?H 0 -T?S 0
Ellingham pointed out that, the standard enthalpy and entropy of formation of a compound do not change significantly with the temperature as long as there is no change of state of product or reactant. ?G 0 T =?H 0 289 -T?S 0 298
Thus, the general forms of ?G 0 T ?S 0 relationships could be approximated to straight lines over temperature ranges
?G 0 = c + mx ; c =?H 0 289 m=-?S 0 298
The slope of free energy vs temperature plot would thus be (-?S 0 ) entropy change of the reaction and the intercept is the enthalpy value.
It provides a sound idea about selecting a reducing agent in the reduction of oxides. Such diagrams helps in predicting the feasibility of a thermal reduction of an ore. ?G must be negative at a given temperature for a reaction to be feasible.
Ellingham plotted the experimentally determined standard free energy of
formation, ?G 0 , of various oxides using one mole of oxygen with temperature.
(2x/y) M(s) + O 2 (g) ------> (2/y) M x O y (s) ; ?G 0 =?H 0 -T?S 0
Ellingham pointed out that, the standard enthalpy and entropy of formation of a compound do not change significantly with the temperature as long as there is no change of state of product or reactant. ?G 0 T =?H 0 289 -T?S 0 298
Thus, the general forms of ?G 0 T ?S 0 relationships could be approximated to straight lines over temperature ranges
?G 0 = c + mx ; c =?H 0 289 m=-?S 0 298
The slope of free energy vs temperature plot would thus be (-?S 0 ) entropy change of the reaction and the intercept is the enthalpy value.
It provides a sound idea about selecting a reducing agent in the reduction of oxides. Such diagrams helps in predicting the feasibility of a thermal reduction of an ore. ?G must be negative at a given temperature for a reaction to be feasible.
Answered by Expert
12th October 2012,
5:12 PM
Rate this answer
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
You have rated this answer /10
Your answer has been posted successfully!
RELATED STUDY RESOURCES :
KERALA Class-12-science QUESTION ANSWERS
Browse free questions and answers by Chapters
- 1 The Solid State
- 2 Solutions
- 3 Electrochemistry
- 4 Chemical Kinetics
- 5 Surface Chemistry
- 6 Isolation of Elements
- 7 The p-Block Elements
- 8 The d-Block and f-Block Elements
- 9 Coordination Compounds
- 10 Haloalkanes and Haloarenes
- 11 Alcohols, Phenols and Ethers
- 12 Aldehydes, Ketones and Carboxylic Acids
- 13 Amines
- 14 Biomolecules
- 15 Polymers
- 16 Chemistry in Everyday Life
Trending Tags
Latest Questions
JEE Main Mathematics
Asked by amaladelsingh
28th October 2020,
10:24 PM
CBSE X Biology
Asked by reenacharan2008
28th October 2020,
9:11 PM
