1. ENTROPY MEANING OF THE TERM?
CLUE
WHAT 8 LETTER WORD INDICATES THE CONDITION OF THE CLASS IN THE ABSENCE OF THE TEACHER

2. ENTROPY DISORDER DENOTED BY S IS A MEASURE OF DISORDER OF A SYSTEM
IT CAN BE ZERO AT ZERO KELVIN AND THIS ASSUMES A PERFECTLY ORDERED CRYSTAL
AS TEMPERATURE OF THE MATERIAL INCREASES,THE PARTICLES GAIN KINETIC ENERGY AND THEIR MOTION INCREASES
HIGH TEMPERATURE INCREASE THE DISORDER OF THE SYSTEM

3. CHANGE IN ENTROPY HOW DOES ENTROPY CHANGE WITH CHANGE OF STATE FROM
SOLID LIQUID GAS

4. CHANGE IN ENTROPY

5. CHANGE IN ENTROPY WITH TEMP.

6. CHANGE IN ENTROPY
ENTROPY INCREASES WHEN THE NUMBER OF PARTICLES INCREASE
CHANGE EG
CHANGE IN ENTROPY
REASON
REACTION RELEASING A GAS
Zn AND ACID
POSITIVE –INCREASING ENTROPY
GAS MOLECULES ARE MORE DISORDERED THAN THAT IN SOLUTION
GAS REACTION WHERE NO. OF MOLECULES DECREASE
FORMATION OF AMMONIA
NEGATIVE-DREASING ENTROPY
LESS MOLECULES OF PRODUCTS THAN REACTANTS REDUCING DISORDER

7. CALCULATING CHANGE IN ENTROPY S
ENTROPY VALUES DEPEND ON TEMPERATURE AND PHYSICAL STATE
ENTROPY INCREASE AS NO. OF BONDS IN THE SUBSTANCE INCREASE.EG ETHANOL HAS GREATER ENTROPY THAN METHANOL
STANDARD ENTROPY IS THE ENTROPY OF A SUBSTANCE AT STANDARD TEMPERATURE AND PRESSURE AND IS EXPRESSED PER MOLE OF THE SUBSTANCE

8. CALCULATING CHANGE IN ENTROPY S
THE STANDARD ENTROPY CHANGE FOR PHYSICAL OR CHEMICAL CHANGE IS THE DIFFERENCE IN ENTROPIES OF THE PRODUCTS AND REACTANTS MEASURED UNDER STANDARD CONDITION
ENTROPY CHANGE OF SYSTEM =TOTAL ENTROPY OF PRODUCTS-TOTAL ENTROPY OF REACTANTS
∆S=∑S OF PRODUCTS-∑ S OF REACTANTS

9. RELATION BETWEEN ENTHALPY AND ENTROPY
EXOTHERMIC REACTIONS GIVE OUT HEAT ,INCREASES THE ENTROPY OR DISORDER OF THE SURROUNDING PARTICLES AND ARE SPONTANEOUS
SOME ENDOTHERMIC REACTIONS WHICH HAVE POSITIVE VALUE FOR ∆H ALSO ARE SPONTANEOUS AT ROOM TEMPERATURE.
ENTHALPY CHANGES ALONE DO NOT DITERMINE WHETHER A REACTION IS SPONTANEOUS OR NOT

10. TOTAL ENTROPY CHANGE DITERMINES WHETHER A REACTION IS SPONTANEOUS OR NOT.
∆S TOTAL =∆SSYSTEM +∆SSURROUNDING
∆S SURROUNDING = -∆H T
FOR ANY SPONTANEOUS CHANGE TOTAL ENTROPY SHOULD BE POSITIVE

11. FEASIBILITY OF A REACTION

12. FEASIBILITY OF A REACTION
FEASIBILITY OF A REACTION IS RELATED TO BOTH ENTROPY AND ENTHALPY CHANGES
IF ∆ S TOTAL> O ,REACTION WILL BE FEASIBLE

13. For Edexcel:
Feasibility and spontaneity are EXACTLY the same thing. You can use the two terms interchangeably.

14. FEASIBILITY OF A REACTION
THE MAIN FACTORS WHICH DITERMINE FEASIBILITY OF A REACTION ARE
1.ENTROPY CHANGE OF THE SYSTEM
2.TEMPERATURE MEASURED IN KELVIN
3.ENTHALPY CHANGE WITH THE SURROUNDING.

15. THERMODYNAMIC STABILITY AND KINETIC STABILITY
IF ∆ S total IS POSITIVE REACTION IS FEASIBLE AND THE REACTANTS ARE SAID TO BE THERMODYNAMICALLY UNSTABLE RELATIVE TO THE PRODUCTS
IF ∆ S total IS NEGATIVE REACTION IS NOT FEASIBLE AND THE REACTANTS ARE SAID TO BE THERMODYNAMICALLY STABLE RELATIVE TO THE PRODUCTS

16. THERMODYNAMIC STABILITY AND KINETIC STABILITY
A SMALL ACTIVATION ENERGY MEANS A REACTION IS SPONTANEOUS AND REACTANTS ARE KINETICALLY UNSTABLE RELATIVE TO THE PRODUCTS
A HIGH ACTIVATION ENERGY MEANS REACTANTS ARE KINETICALLY STABLE RELATIVE TO THE PRODUCTS

17. THERMODYNAMIC STABILITY AND KINETIC STABILITY
USE THE FOLLOWING DATA TO EXPLAIN WHY THE CONVERSION OF DIAMOND TO GRAPHITE IS FEASIBLE AT ALL TEMP. BUT DOES NOT OCCUR AT ROOM TEMP.
STANDARD ENTROPY
DIAMOND J/mol/k
GRAPHITE
∆H diamond to graphite=-2kj/mol

18. THERMODYNAMIC STABILITY AND KINETIC STABILITY
∆H diamond to graphite is negative showing the reaction is exothermic and diamond is thermodynamically unstable
S system= =3.3
S surrounding= + value
S total is positive so reaction is feasible at room temp.
Reaction does not take place at room temp. because it has high activation energy, so the reactant is kinetically stable

19. THERMODYNAMIC STABILITY AND KINETIC STABILITY
EG. COMBUSTION OF METHANE
∆S TOTAL IS POSITIVE AND SO THE REACTION IS THERMODYNAMICALLY FEASIBLE OR THE REACTANTS ARE SAID TO BE THERMODYNAMICALLY UNSTABLE RELATIVE TO THE PRODUCTS
THE REACTION DOES NOT TAKE PLACE AT ROOM TEMPERATURE SO THE ACTIVATION ENERGY MUST BE HIGH SO THE REACTANTS WILL BE KINETICALLY INERT RELATIVE TO THE PRODUCTS