Carnot Cycle Class 11 Notes | EduRev

Chemistry Class 11

Class 11 : Carnot Cycle Class 11 Notes | EduRev

The document Carnot Cycle Class 11 Notes | EduRev is a part of the Class 11 Course Chemistry Class 11.
All you need of Class 11 at this link: Class 11

CARNOT CYCLE
Carnot cycle is based on 4 reversible process. 

Carnot Cycle Class 11 Notes | EduRev

(1) Reversible isothermal expansion from A to B. 
ΔEAB = 0 ,

Carnot Cycle Class 11 Notes | EduRev

(2) Reversible adiabatic expansion from B to C 
ΔEBC = nCV(T2 -T1)
WBC = ΔEBC

(3) Isothermal compression from C to D 
ΔECD = 0,

Carnot Cycle Class 11 Notes | EduRev

(4) Adiabatic compression from D to A. 
ΔEDA  = nCV(T- T2)
WDA = ΔEDA
ΔECycle  = 0
Carnot Cycle Class 11 Notes | EduRev
Carnot Cycle Class 11 Notes | EduRev
For BC, 

Carnot Cycle Class 11 Notes | EduRev

For ΔA,

Carnot Cycle Class 11 Notes | EduRev
Wcycle = -nR(T1 - T2)ln V2/V1

Efficiency of any engine may be given as 

Carnot Cycle Class 11 Notes | EduRev
Carnot Cycle Class 11 Notes | EduRev

Carnot Cycle Class 11 Notes | EduRev

ΔEcycle = qcyc wcycle 

Carnot Cycle Class 11 Notes | EduRev

Carnot Cycle Class 11 Notes | EduRev

This means ΔS is a state function

Gibb's Free Energy (G)
Gsystem = Hsystem - TSsystem
W = Wexpansion +Wnon-expansion
Wnon - expansion = wuseful (useful work)
ΔG = Wnon expansion = Wuseful
All those energy which is available with the system which is utilized in doing useful work is called Gibb's free energy :

Rx
1. ΔGsystem ΔHsystem - TΔSsystem = - TΔSuniverse = Wnon expansion = Wuseful 
2. ΔGsystem = - TΔSuniverse 
3. 
(a) ΔSuniverse > 0 or ΔGsystem < 0 ⇒ Spontaneous
(b) ΔSuniverse = 0 or ΔGsystem = 0 ⇒ Equilibrium
(c) ΔSuniverse < 0 or ΔGsystem > 0 ⇒ Non-Spontaneous
Carnot Cycle Class 11 Notes | EduRev

APPLICATION OF ( ΔG )
Rx
(1) aA + bB  ⇌ cC + dD
ΔG° = Standard Gibb's free energy change (P = 1 atm, 298 K)
ΔG = Gibb's free energy change at any condition.

NERNST EQUATION
ΔG =  ΔG° + 2.303 RT log Q ; Q = Reaction Quotient

Carnot Cycle Class 11 Notes | EduRev
At equilibrium, ΔG = 0 and Q = Keq.
0 = ΔG° 2.303 RT log keq
ΔG° = -2.303 RT log keq
å G°(product) - å G° (Reactant) = - 2.303 RT log keq
ΔH° - T ΔS° = -2.303 RT log keq 

  Carnot Cycle Class 11 Notes | EduRev

(2) Wcell = q × E
ΔG = - Wcell
ΔG = - q × Ecell
Now, one mole e- have charge 96500 coulomb = 1 Faraday (F)
n mole of e- will have charge = n × F or q = n × F
ΔG = - nFEcell
ΔG° = -nFE°cell

THIRD LAW OF THERMODYNAMICS
limitT→0 S = 0
Third law of thermodynamics states that as the temperature approaches absolute zero, the entropy of perfectly crystalline substance also approaches zero.

APPLICATION OF THIRD LAW OF THERMODYNAMICS

Carnot Cycle Class 11 Notes | EduRev
Taking T2 = T and T1 = 0°k.

Carnot Cycle Class 11 Notes | EduRev
For perfectly crystalline substance. The entropy of perfectly crystalline substance can be determined using third law of thermodynamics.
or 
With the help of third law of thermodynamics we can calculate the exact value of entropy.

ΔG AND NON PV WORK (NON EXPANSION/COMPRESSION)
(ΔG)T,P  is a measure of useful work a non PV work (non expansion work) that can be produced by a chemical transformation.e.g.electrical work .

For reversible reaction at constant T & P
dU = dq + dWtotal
dU = dq + dWP, V + dWnon P,V 
dU = T.dS - P. dV + dWnon P,V 
dU + P.dV = T. dS + dWnon P,V
dH = T.dS + dWnon P,V
(dGsys)T,P = dWnon P,V 
Carnot Cycle Class 11 Notes | EduRev
Useful work done on the system = increase in Gibb's energy of system at constant T & P.
- (ΔGsys)T,P= - Wnon P,V
- (ΔGsys)T,P= - Wby, non P,V
Useful work done by the system = decrease in Gibb's energy of system at constant T & P.
If (ΔGsys)T,P = 0, then system is unable to deliver useful work.

THERMODYNAMIC RELATION
For reversible process in which non-expansion work is not possible
dU = dq + dW

Carnot Cycle Class 11 Notes | EduRev
H = U + PV
dH = dU + P.dV + VdP
dH = T.dS - PdV + PdV + V.dP
dH = T.dS + V.dP
G = H -TS
dG = dH - T.dS -S.dT
dG = T.dS + V.dP - T.dS - S.dT

Carnot Cycle Class 11 Notes | EduRev
 For a particular system (s/ℓ/g)

(1) At constant temperature dG = V.dP
or
Carnot Cycle Class 11 Notes | EduRev
(A) For a system is s/ ℓ phase

Carnot Cycle Class 11 Notes | EduRev

Carnot Cycle Class 11 Notes | EduRev
(B) For an ideal gas, expansion/compression:-
Carnot Cycle Class 11 Notes | EduRev

(2) At constant pressure : dG =-S.dT
or
Carnot Cycle Class 11 Notes | EduRev
For phase transformation/chemical reaction
d(ΔG) = ΔV.dP - ΔS dT
H2O(s) → H2O(l)
ΔV = VM(H2O,l) - Vm(H2O,s)
ΔS = SM(H2O,l) - Sm(H2O,s)
A(s) → B(g) + 2C(g)
ΔrS = SM(B,g ) 2Sm(C,g) - Sm(A,s)
C (s, graphite) → C(s, diamond)
ΔV = Vm(C, diamond) - Vm(C-graphite)
At constant temperature:-
d(ΔG) = ΔV. dP

Carnot Cycle Class 11 Notes | EduRev
At constant pressure

Carnot Cycle Class 11 Notes | EduRev
ΔrGT2 - ΔrGT1 = - ΔrS(T2 - T1)

Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Related Searches

Important questions

,

shortcuts and tricks

,

Exam

,

Viva Questions

,

Summary

,

Objective type Questions

,

Carnot Cycle Class 11 Notes | EduRev

,

pdf

,

Free

,

study material

,

past year papers

,

practice quizzes

,

Carnot Cycle Class 11 Notes | EduRev

,

Semester Notes

,

MCQs

,

ppt

,

mock tests for examination

,

video lectures

,

Sample Paper

,

Extra Questions

,

Carnot Cycle Class 11 Notes | EduRev

,

Previous Year Questions with Solutions

;