University:
York University
Course:
SC/CHEM 2011 | Introduction to Thermodynamics
Academic year:

2022
Views:

413

Pages:

3
Author:

Niklas

(2.4) free energy free energy a process in an isolated system is spontaneous if ASsys > O - change of surroundings under constant temp a pressure: entropy change of surroundings ASsur AH/T = - ΔΗ ων -ΔΗ, 50, AS-H/T ΔΗ then: ΔΗτης T gibbs gibbs free energy gy σ G-H-TS ΔΕ = ΣGproducts - Σwachante AG - AH-TAS For every process spontaneous @ constant temp & prestowe, AGD reaction will procced spontancously favours products AG-D system is equilibrium. It of moks of reactants & products don't change AGD reaction is NOT spontaneous, reverse ran is spontaneous favours reactants Reactants Free Energy AG0 Spontaneous Process Products Free Energy Products Nonspontaneous Process Reactants what drives a process? ΔΗ AS + ΔΕ + + enthalpically & entropically driven +/- entropically driven, if spontaneous + + +/- enthalpically driven, if spontaneous enthalpically driven processes storng exothermic (mases & negative) S<0 are enthalpically driven spontaneous processes w/ AHCO & AS<0 ΔΕ - (ΔΗ - ΤΔΣ) >0 endothermic rxns (ΔΗ>0) ave entropically driven processes only spontaneous when DS O" are entropically driven •ΔΗ & AS are independent of tampovahuve (melting is onhopically driven) @melting point, ΔΕ-Ο ΔΗξης Tom AStus →@boiling temp (To) ΔΗεναρ. Το ΔΣ εναρ →AG-(8H-TAS) > 0 enthalpically & entropically driven prousses Some rxns are spontaneous bes they have favourable enthalpy entropy changes (AH0) (ie) rans that are highly exothermic (ΔΗ << 0) so that AG (ΔΗ - ΤΔΣ) < 0 & inovease of entropy (AS>0) these rxns are both enthalpically & antropically driven Standard free energy change change under standard conditions free energy change AG - ΔH - TAS (1 atm/1M/298K) glanded value energy of formation standard free energy ΔΕ 15 change when 1 mole the standard free energy change made rom elements in their standard states from analogous to ΔΗ definition is analogous to of compound is →AG; (element in standard stare) = 0 (in) Has →H₂O) Standowd states, so 460 -237 →AG = ΣΔΕ (products) ΣΔΕ; (reactants) AG-AG (products) - ΣΔ Gir (rec