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

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

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

CHANGE IN ENTROPY

CHANGE IN ENTROPY WITH TEMP.

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

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

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

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

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

FEASIBILITY OF A REACTION

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

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

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.

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

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

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 2.4J/mol/k GRAPHITE 5.7 ∆H diamond to graphite=-2kj/mol

THERMODYNAMIC STABILITY AND KINETIC STABILITY ∆H diamond to graphite is negative showing the reaction is exothermic and diamond is thermodynamically unstable S system=5.7-2.4=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

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