Title 2A.THERMODYNAMICS & THERMO CHEMISTRY LEVEL-V(MDP) FINAL.pdf ✅

NISHITH Multimedia India (Pvt.) Ltd., 4 3 JEE MAINS - CW - VOL - I JEE ADVANCED - VOL - II NISHITH Multimedia India (Pvt.) Ltd., THERMODYNAMICS (ENERGETICS) SYNOPSIS 1. Thermodynamic changes in adiabatic changes in volume of an ideal gas 1  0 E q w st law q in adiabatic process E w       we know that       , . , 2 1 2 1 2 2 1 1 2 , 1 1 , 1 1 1 1 1 1 1 1 vm vm pm v m pm v m v m v m v m E n c T w n c T C C R C C C C R R Cv m R w n T nR w T T w nRT nRT w P V PV T w nC T T                                          2. Adiabatic reversible process , , v m ext ext Int Int v m dE dw dE nC dT and dw p dv P P nRT P V nRT nC dT dv v          2 2 1 1 , , 2 2 , 1 1 ln ln v m T v v m T v v m RT C dT dv v dT dv C R T v T V C R T V                     , , , , , 2 2 1 1 2 2 1 1 2 1 1 2 / 1 ln ln tan tan tan v m v m v m v m v m C R C R C R C R R C r T V T V T V T V T V T V T v cons t TV cons t TV cons t                                               3. Relation between T and P , , , . , ( ) / 1 tan tan tan tan tan tan v m v m v m p m p m C R R C C R R C R R C T V cons t RT T cons t P T P cons t T P cons t T P cons t T P cons t                    Relation between P and V , , , , , , tan tan tan tan tan v m v m v m p m p m v m C R C R C C C C T V cons t PV V cons t R P V cons t PV cons t PV cons t             THERMODYNAMICS (ENERGETICS) , , , , , , 1 1 1 1 p m v m p m p m v m p m R C c C C C C                        
THERMODYNAMICS (ENERGETICS) 4 4 NISHITH Multimedia India (Pvt.) Ltd., JEE ADVANCED - VOL - II NISHITH Multimedia India (Pvt.) Ltd., 4. Entropy change in terms of temperature and volume changes 1st law dU dq w   ( ) rev rev dq Pdv dq dU PdV      rev vm dq dU PdV T T T nc dT nR dS dV T v     2 2 2 1 1 1 , S T V v m S T V dT dv dS nC nR T v      2 2 , 1 1 ln ln Cv m T V S n nR T V    For Isothermal changeT T 1 2  2 1 ln V S nR V   For Isochoricprocess V V 1 2  2 , 1 l n v m T S n C T   5. Entropy change in terms of temperature and pressure changes 2 1 2 1 2 1 2 2 , 1 1 ln ln v m V PT V PT T V S n c n R T V       , 2 2 , 1 1 2 1 2 1 2 1 2 1 , 1 2 ln ln ln ln ln v m v m v m T V S nc nR T V T PT nc nR T P T T P n C R nR T P         2 1 , 1 2 ln ln p m T P S nc nR T P    For Iso baric process P P 1 2  2 , 1 ln p m T S nC T   6. Entropy changes in Isothermal process Isothermal reversible process In Expan sion system takes q heat from surround ings Re 2 1 ln v q w V w nRT V     2 1 2 1 R e ln ln rev S YS S YS v V n R T q V S T T V S n R V q S su rro u n d in g T         2 . 1 . 2 2 1 1 ln ( ) ln ln 0 s u rr T ota l un iver s e S Y S s u rr V S n R V S o r S S S V V n R n R V V              In compression, system gives Q heat to surroundings 2 1 2 1 ln ln 0 sys surro Total V S nR V V S nR V S         7. Isothermal Irreversible prosses (A) Free Expansion w = 0 q = 0 since Entropy is a state function, the entropy changes of a system in going from volume V toV 1 2 by any path will be same as that of reversible porcess 2 1 2 1 ln ln SYS surro total V S nR V S o V S nR V      
NISHITH Multimedia India (Pvt.) Ltd., 4 5 JEE MAINS - CW - VOL - I JEE ADVANCED - VOL - II NISHITH Multimedia India (Pvt.) Ltd., THERMODYNAMICS (ENERGETICS) (B) Irriversible expansion rev q is the amount of heat the system would have absorbed. In the P resent case Expansion done against constant pressure 2 1 ( ) rev ext Q w P V V     2 1 2 2 1 1 ( ) ( ) ln Irr ext surrounding ext Total q P V V S T T V P V V S nR V T           SYS surro Total S is ve and S is ve S is ve       C. Irriversible Compression 2 1 2 1 ln ( ) SYS ext surro SYS surro SYS surro V S nR V p V V S T S S S is ve and S is ve               2 2 1 1 ( ) ln ext Total Total V P V V S nR V T S is ve         8. Entropy changes in adiabtic process q = o surro   S o (A) Reversible process 2 2 , 1 1 2 1 , 1 2 ln ln ln SYS v m SYS p m T V S nC nR in T V T P S nC nR T P      in Expansion, the increase entrcpy due to volume change just compensate the decrease in entropy due to the fall in temperature SYS   S o  The process is known as “Isoentropic process.  o (B) . Irreversible adiabatic free Expansion   2 1 2 1 , 1 2 1 2 2 1 2 1 , ln ln ln ( ) ln ln sys p m SYS SYS Total SYS surro Total Total w O T O T T T P S nC nR T P P S nR P or S is ve S S S V nR o V V S nR V S is ve                       (C) Intermediate Expansion 2 2 , 1 1 2 1 , 1 2 ln ln ( ) ln S Y S v m S Y S p m T V S n C n R T V o r T P S n C n R T P       In Expansion the increase in entropy due to volume change is larger than the de crease in cntropy due to temp change SYS Total S is ve S is also ve     In copression, the decrease in entropy due to volume change is smaller than the increase in entropy due teperature SYS Total S is ve S is also ve     9. Trouton’s rule is vap vap b H S T    i.e 10.5 vap S R  at boiling point 10. For   2   3  , , Hg H O NH l l l have high vap S and doesn’t follow trouton’s rule 11. sGisothermal (in isolated gaseous system) 2 max 1 . 2.303 log V W nRT V         
THERMODYNAMICS (ENERGETICS) 4 6 NISHITH Multimedia India (Pvt.) Ltd., JEE ADVANCED - VOL - II NISHITH Multimedia India (Pvt.) Ltd., 2. No heat is absorbed by the system from the surroundings, but work (w) is done on the system. What type of wall does the system have? (A) U = Wad ; wall is insulated (B) U = - q, thermally conducting walls (C) U = q - w, closed system. (D) U = q - w, open system 3. Which one of the following bonds has the highest average bond energy (kcal/mol) (A) S = S (B) C C (C) C N (D) N N 4. For the reaction 2O 3O H 16 KJ / mole 3 2 f      . We can say that (A) ozone is more stable than oxygen (B) ozone is less stable than oxygen and ozone decomposes forming oxygen readily (C) oxygen is less stable than ozone and oxygen readily forms ozone (D) none of the above 5. Which reaction either endothermic or exothermic characteristics has the greater chance of occuring spontaneously? (A) One in which entropy change is positive (B)One in which entropy change is negative (C) One in which free energy change is negative (D) One in which equilibrium has been established 6. S for the reaction,       MgCO s MgO s CO g 3 2   will be (A) zero (B) –ve (C) +ve (D)  7. Change in entropy is negative for: (A) Bromine (l)  Bromine (g) (B) C s O g CO g     2 2     (C)     N g,10atm N g,1atm 2 2  (D) Fe 1mol,400K Fe 1mol,300K      12. 3rd low of T.D equation is 2.303 log T v S nc T  , 3 v m T C S  13. Criterion of spontaneity I. 0: tan ( ) 0 0:Re Pr 0: tan total Spon eous Irreversible S versible ocess Non spon eous       II.   , 0: tan ( ) 0 0:Re Pr 0: tan system T P Spon eous Irreversible G versible ocess Nonspon eous       III.   , 0 : tan ( ) 0 0 :Re Pr 0 : tan system S V Spon eous Irreversible E versible ocess Non spon eous       IV.   , 0 : tan ( ) 0 0 :Re Pr 0 : tan system S P Spon eous Irreversible H versible ocess Non spon eous       V.   , 0 : tan ( ) 0 0 :Re Pr 0 : tan system T V Spon eous Irreversible A versible ocess Non spon eous       VI.   , 0 : tan ( ) 0 0:Re Pr 0 : tan system E V Spon eous Irreversible S versible ocess Non spon eous       SINGLE ANSWER QUESTIONS 1. The work done by a weightless piston in causing an expansion V (at constant temperature), when the opposing pressure, P is variable, is given by: (A) W PdV   (B) W = 0 (C) W P V    (D) None of these